APPLICATION OF MATHEMATICAL MODELING IN RAINFALL FORECAST A CASE STUDY OF SUNGAI SARAWAK BASIN

Beatrice Christianus Bidaun

Master of Engineering (Civil Engineering)

2013

ACKNOWLEDGEMENT

First and foremost praises and thanks to the Lord God almighty for His showers of blessings

I would like to express my deepest gratitude to my supervisor Assoc Prof Dr Nasser Rostam

Afshar and co-supervisor Dr Onni Suhaiza Selaman for their excellent guidance patience

motivation and immense knowledge throughout the study

I want to thank the Department of Civil Engineering UNIMAS and the Faculty of Civil

Engineering UiTM Sarawak for their continuous support and kindness I have gained so much

knowledge from everyone Thank you to the Department of Irrigation and Drainage Sarawak

for providing the required hydrology data as well as technical knowledge

My appreciation also goes to my batch thank you for being such awesome friends and

classmates To dearest friends thank you for the support and encouragement To my family

thank you for being the rock of my life

ABSTRACT

Rainfall is a random and probabilistic phenomenon that plays a great role in the life of

humans The study embarks to apply a mathematical modeling in rainfall forecasting for

the Sungai Sarawak basin Recent study reveals that the FS has the ability to simulate

long-term rainfall up to 300 years is viewed as an important finding in the study of rainfall

forecast Rainfall data was collected from eight rain gauge stations from the Department

of Irrigation and Drainage Sarawak The data was then analyzed and prepared for missing

data consistency check and adequacy of number of stations Simple statistical analysis

was conducted on the data such as maximum minimum mean and standard deviation 27

years of annual rainfall data were simulated with the Fourier Series equation using

spreadsheet Hence the result was compared with the Fitting N -term Harmonic Series

The model result reveals that the Fourier Series has the ability to simulate the observed

data by being able to describe the rainfall pattern The result was tested using x2 and

RMSE 295 and 1133 mm respectively There is a reasonable relationship between the

simulation and observed data with p-value of 093 For future study it is highly

recommended to have a refinement in the data analysis that can highly influences the

perfonnance of the model

II

ABSTRAK

Hujan adalah satu fenomena alam yang memainkan peranan yang besar dalam kehidupan

manusia Kajian ini dijalankan sebagai salah satu langkah menghadapi kesan-kesan

perubahan iklim Kawasan kajian yang terbabit adalah Lembagan Sungai Sarawak dan

kaedah model hujan yang telah digunapakai ialah Fourier Series Kajian baru-baru ini

telah mendapati FS berupaya untuk mensimulasikan hujan dalam jangka panjang iaitu

sehingga 300 tahun dilihat sebagai penemuan penting Data hujan daripada lapan stesen

hidrologi daripada Jabatan Pengairan dan Saliran Sarawak telah dianalisa bagi data yang

hilang dan juga keseragaman data Analisis statistik telah dijalankan ke atas data seperti

maksimum minimum dan min 27 tahun data hujan tahunan disimulasikan dengan

persamaan FS dengan menggunakan perisian excel Simulasi model ini telah

dibandingkan dengan Fitting N-term Harmonic Series Hasil model mendapati FS

mempunyai keupayaan untuk mensimulasikan corak hujan Hasil dapatan kajian ini telah

diuji dengan menggunakan x2 dan RMSE 295 dan 1133 mm Terdapat hubungan yang

wajar di antara simulasi dan data dengan p-nilai 093 Untuk kajian di masa hadapan

dicadangkan untuk melakukan analisa data yang lebih terperinci bagi meningkatkan

prestasi model

III

Pu ut Khidmu MakJumat Ak demik I 1 VSIA SARAWAK

TABLE OF CONTENT

CONTENT Page

ACKNOWLEDGEMENT

ABSTRACT 11

ABSTRAK 1lI

LIST OF FIGURES vii

LIST OF TABLES VllI

LIST OF ABBREVIA nONS IX

CHAPTER 1 INTRODUCTION

11 General

12 Problem Statement 4

13 Objectives 5

14 Scope Of Study 6

15 Significance Of Study 9

16 Report Outline 12

CHAPTER 2 LITERATURE REVIEW

21 Introduction 13

22 Hydrological Model 14

23 Preceding Study 16

24 Fourier Series 19

-

IV

25 Performance Evaluation Of Models 23

25 Summary 24

CHAPTER 3 METHODOLOGY

31 Introduction 26

32 Data Collection 28

33 Preparation Of Data 29

34 Fourier Series 31

35 Modeling Procedures 35

36 Summary 41

CHAPTER 4 RESULTS AND ANALYSIS

41 Introduction 42

42 Analysis Of Data 42

43 Simulation Results 45

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

51 Overview 49 i

52 Conclusions 50

53 Recommendations For Future Study 50

REFERENCES

APPENDICES

v

LIST OF FIGURES

Title Page

Figure 11 HadCM3 PRECIS simulations of annual raindays for Malaysia 3

Figure 12 HadCM3 PRECIS simu1ations of annual and DJF seasonal 3

precipitation anomaly for Malaysia

Figure 13 Sungai Sarawak basin area and location of hydrological stations 8

Figure 14 Map of SCORE 10

Figure 15 Projected flow 11

Figure 21 Hydrological model development 15

Figure 22 Observed and fitted mean rainy day 21

Figure 23 Annual and average rainfall in Iran 23

Figure 31 Research framework 27

Figure 32 Annual rainfall periodic function of case study 36

Figure 33 Fitting N-term Harmonic Series simulation procedures 38

Figure 34 Fitting N-term Harmonic Series 39

Figure 35 Setting the harmonic series 39

Figure 36 Coefficients of Fourier Series 40

Figure 37 RMS andx2 40 ~

Figure 38 Output 41

Figure 41 Consistency check - Sembam 43

Figure 42 Consistency check - Padawan 43

Figure 43 Consistency check - Sungai China 43

Figure 44 Simulation output for 2003 to 2011 46

VI

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

ACKNOWLEDGEMENT

First and foremost praises and thanks to the Lord God almighty for His showers of blessings

I would like to express my deepest gratitude to my supervisor Assoc Prof Dr Nasser Rostam

Afshar and co-supervisor Dr Onni Suhaiza Selaman for their excellent guidance patience

motivation and immense knowledge throughout the study

I want to thank the Department of Civil Engineering UNIMAS and the Faculty of Civil

Engineering UiTM Sarawak for their continuous support and kindness I have gained so much

knowledge from everyone Thank you to the Department of Irrigation and Drainage Sarawak

for providing the required hydrology data as well as technical knowledge

My appreciation also goes to my batch thank you for being such awesome friends and

classmates To dearest friends thank you for the support and encouragement To my family

thank you for being the rock of my life

ABSTRACT

Rainfall is a random and probabilistic phenomenon that plays a great role in the life of

humans The study embarks to apply a mathematical modeling in rainfall forecasting for

the Sungai Sarawak basin Recent study reveals that the FS has the ability to simulate

long-term rainfall up to 300 years is viewed as an important finding in the study of rainfall

forecast Rainfall data was collected from eight rain gauge stations from the Department

of Irrigation and Drainage Sarawak The data was then analyzed and prepared for missing

data consistency check and adequacy of number of stations Simple statistical analysis

was conducted on the data such as maximum minimum mean and standard deviation 27

years of annual rainfall data were simulated with the Fourier Series equation using

spreadsheet Hence the result was compared with the Fitting N -term Harmonic Series

The model result reveals that the Fourier Series has the ability to simulate the observed

data by being able to describe the rainfall pattern The result was tested using x2 and

RMSE 295 and 1133 mm respectively There is a reasonable relationship between the

simulation and observed data with p-value of 093 For future study it is highly

recommended to have a refinement in the data analysis that can highly influences the

perfonnance of the model

II

ABSTRAK

Hujan adalah satu fenomena alam yang memainkan peranan yang besar dalam kehidupan

manusia Kajian ini dijalankan sebagai salah satu langkah menghadapi kesan-kesan

perubahan iklim Kawasan kajian yang terbabit adalah Lembagan Sungai Sarawak dan

kaedah model hujan yang telah digunapakai ialah Fourier Series Kajian baru-baru ini

telah mendapati FS berupaya untuk mensimulasikan hujan dalam jangka panjang iaitu

sehingga 300 tahun dilihat sebagai penemuan penting Data hujan daripada lapan stesen

hidrologi daripada Jabatan Pengairan dan Saliran Sarawak telah dianalisa bagi data yang

hilang dan juga keseragaman data Analisis statistik telah dijalankan ke atas data seperti

maksimum minimum dan min 27 tahun data hujan tahunan disimulasikan dengan

persamaan FS dengan menggunakan perisian excel Simulasi model ini telah

dibandingkan dengan Fitting N-term Harmonic Series Hasil model mendapati FS

mempunyai keupayaan untuk mensimulasikan corak hujan Hasil dapatan kajian ini telah

diuji dengan menggunakan x2 dan RMSE 295 dan 1133 mm Terdapat hubungan yang

wajar di antara simulasi dan data dengan p-nilai 093 Untuk kajian di masa hadapan

dicadangkan untuk melakukan analisa data yang lebih terperinci bagi meningkatkan

prestasi model

III

Pu ut Khidmu MakJumat Ak demik I 1 VSIA SARAWAK

TABLE OF CONTENT

CONTENT Page

ACKNOWLEDGEMENT

ABSTRACT 11

ABSTRAK 1lI

LIST OF FIGURES vii

LIST OF TABLES VllI

LIST OF ABBREVIA nONS IX

CHAPTER 1 INTRODUCTION

11 General

12 Problem Statement 4

13 Objectives 5

14 Scope Of Study 6

15 Significance Of Study 9

16 Report Outline 12

CHAPTER 2 LITERATURE REVIEW

21 Introduction 13

22 Hydrological Model 14

23 Preceding Study 16

24 Fourier Series 19

-

IV

25 Performance Evaluation Of Models 23

25 Summary 24

CHAPTER 3 METHODOLOGY

31 Introduction 26

32 Data Collection 28

33 Preparation Of Data 29

34 Fourier Series 31

35 Modeling Procedures 35

36 Summary 41

CHAPTER 4 RESULTS AND ANALYSIS

41 Introduction 42

42 Analysis Of Data 42

43 Simulation Results 45

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

51 Overview 49 i

52 Conclusions 50

53 Recommendations For Future Study 50

REFERENCES

APPENDICES

v

LIST OF FIGURES

Title Page

Figure 11 HadCM3 PRECIS simulations of annual raindays for Malaysia 3

Figure 12 HadCM3 PRECIS simu1ations of annual and DJF seasonal 3

precipitation anomaly for Malaysia

Figure 13 Sungai Sarawak basin area and location of hydrological stations 8

Figure 14 Map of SCORE 10

Figure 15 Projected flow 11

Figure 21 Hydrological model development 15

Figure 22 Observed and fitted mean rainy day 21

Figure 23 Annual and average rainfall in Iran 23

Figure 31 Research framework 27

Figure 32 Annual rainfall periodic function of case study 36

Figure 33 Fitting N-term Harmonic Series simulation procedures 38

Figure 34 Fitting N-term Harmonic Series 39

Figure 35 Setting the harmonic series 39

Figure 36 Coefficients of Fourier Series 40

Figure 37 RMS andx2 40 ~

Figure 38 Output 41

Figure 41 Consistency check - Sembam 43

Figure 42 Consistency check - Padawan 43

Figure 43 Consistency check - Sungai China 43

Figure 44 Simulation output for 2003 to 2011 46

VI

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

ABSTRACT

Rainfall is a random and probabilistic phenomenon that plays a great role in the life of

humans The study embarks to apply a mathematical modeling in rainfall forecasting for

the Sungai Sarawak basin Recent study reveals that the FS has the ability to simulate

long-term rainfall up to 300 years is viewed as an important finding in the study of rainfall

forecast Rainfall data was collected from eight rain gauge stations from the Department

of Irrigation and Drainage Sarawak The data was then analyzed and prepared for missing

data consistency check and adequacy of number of stations Simple statistical analysis

was conducted on the data such as maximum minimum mean and standard deviation 27

years of annual rainfall data were simulated with the Fourier Series equation using

spreadsheet Hence the result was compared with the Fitting N -term Harmonic Series

The model result reveals that the Fourier Series has the ability to simulate the observed

data by being able to describe the rainfall pattern The result was tested using x2 and

RMSE 295 and 1133 mm respectively There is a reasonable relationship between the

simulation and observed data with p-value of 093 For future study it is highly

recommended to have a refinement in the data analysis that can highly influences the

perfonnance of the model

II

ABSTRAK

Hujan adalah satu fenomena alam yang memainkan peranan yang besar dalam kehidupan

manusia Kajian ini dijalankan sebagai salah satu langkah menghadapi kesan-kesan

perubahan iklim Kawasan kajian yang terbabit adalah Lembagan Sungai Sarawak dan

kaedah model hujan yang telah digunapakai ialah Fourier Series Kajian baru-baru ini

telah mendapati FS berupaya untuk mensimulasikan hujan dalam jangka panjang iaitu

sehingga 300 tahun dilihat sebagai penemuan penting Data hujan daripada lapan stesen

hidrologi daripada Jabatan Pengairan dan Saliran Sarawak telah dianalisa bagi data yang

hilang dan juga keseragaman data Analisis statistik telah dijalankan ke atas data seperti

maksimum minimum dan min 27 tahun data hujan tahunan disimulasikan dengan

persamaan FS dengan menggunakan perisian excel Simulasi model ini telah

dibandingkan dengan Fitting N-term Harmonic Series Hasil model mendapati FS

mempunyai keupayaan untuk mensimulasikan corak hujan Hasil dapatan kajian ini telah

diuji dengan menggunakan x2 dan RMSE 295 dan 1133 mm Terdapat hubungan yang

wajar di antara simulasi dan data dengan p-nilai 093 Untuk kajian di masa hadapan

dicadangkan untuk melakukan analisa data yang lebih terperinci bagi meningkatkan

prestasi model

III

Pu ut Khidmu MakJumat Ak demik I 1 VSIA SARAWAK

TABLE OF CONTENT

CONTENT Page

ACKNOWLEDGEMENT

ABSTRACT 11

ABSTRAK 1lI

LIST OF FIGURES vii

LIST OF TABLES VllI

LIST OF ABBREVIA nONS IX

CHAPTER 1 INTRODUCTION

11 General

12 Problem Statement 4

13 Objectives 5

14 Scope Of Study 6

15 Significance Of Study 9

16 Report Outline 12

CHAPTER 2 LITERATURE REVIEW

21 Introduction 13

22 Hydrological Model 14

23 Preceding Study 16

24 Fourier Series 19

-

IV

25 Performance Evaluation Of Models 23

25 Summary 24

CHAPTER 3 METHODOLOGY

31 Introduction 26

32 Data Collection 28

33 Preparation Of Data 29

34 Fourier Series 31

35 Modeling Procedures 35

36 Summary 41

CHAPTER 4 RESULTS AND ANALYSIS

41 Introduction 42

42 Analysis Of Data 42

43 Simulation Results 45

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

51 Overview 49 i

52 Conclusions 50

53 Recommendations For Future Study 50

REFERENCES

APPENDICES

v

LIST OF FIGURES

Title Page

Figure 11 HadCM3 PRECIS simulations of annual raindays for Malaysia 3

Figure 12 HadCM3 PRECIS simu1ations of annual and DJF seasonal 3

precipitation anomaly for Malaysia

Figure 13 Sungai Sarawak basin area and location of hydrological stations 8

Figure 14 Map of SCORE 10

Figure 15 Projected flow 11

Figure 21 Hydrological model development 15

Figure 22 Observed and fitted mean rainy day 21

Figure 23 Annual and average rainfall in Iran 23

Figure 31 Research framework 27

Figure 32 Annual rainfall periodic function of case study 36

Figure 33 Fitting N-term Harmonic Series simulation procedures 38

Figure 34 Fitting N-term Harmonic Series 39

Figure 35 Setting the harmonic series 39

Figure 36 Coefficients of Fourier Series 40

Figure 37 RMS andx2 40 ~

Figure 38 Output 41

Figure 41 Consistency check - Sembam 43

Figure 42 Consistency check - Padawan 43

Figure 43 Consistency check - Sungai China 43

Figure 44 Simulation output for 2003 to 2011 46

VI

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

ABSTRAK

Hujan adalah satu fenomena alam yang memainkan peranan yang besar dalam kehidupan

manusia Kajian ini dijalankan sebagai salah satu langkah menghadapi kesan-kesan

perubahan iklim Kawasan kajian yang terbabit adalah Lembagan Sungai Sarawak dan

kaedah model hujan yang telah digunapakai ialah Fourier Series Kajian baru-baru ini

telah mendapati FS berupaya untuk mensimulasikan hujan dalam jangka panjang iaitu

sehingga 300 tahun dilihat sebagai penemuan penting Data hujan daripada lapan stesen

hidrologi daripada Jabatan Pengairan dan Saliran Sarawak telah dianalisa bagi data yang

hilang dan juga keseragaman data Analisis statistik telah dijalankan ke atas data seperti

maksimum minimum dan min 27 tahun data hujan tahunan disimulasikan dengan

persamaan FS dengan menggunakan perisian excel Simulasi model ini telah

dibandingkan dengan Fitting N-term Harmonic Series Hasil model mendapati FS

mempunyai keupayaan untuk mensimulasikan corak hujan Hasil dapatan kajian ini telah

diuji dengan menggunakan x2 dan RMSE 295 dan 1133 mm Terdapat hubungan yang

wajar di antara simulasi dan data dengan p-nilai 093 Untuk kajian di masa hadapan

dicadangkan untuk melakukan analisa data yang lebih terperinci bagi meningkatkan

prestasi model

III

Pu ut Khidmu MakJumat Ak demik I 1 VSIA SARAWAK

TABLE OF CONTENT

CONTENT Page

ACKNOWLEDGEMENT

ABSTRACT 11

ABSTRAK 1lI

LIST OF FIGURES vii

LIST OF TABLES VllI

LIST OF ABBREVIA nONS IX

CHAPTER 1 INTRODUCTION

11 General

12 Problem Statement 4

13 Objectives 5

14 Scope Of Study 6

15 Significance Of Study 9

16 Report Outline 12

CHAPTER 2 LITERATURE REVIEW

21 Introduction 13

22 Hydrological Model 14

23 Preceding Study 16

24 Fourier Series 19

-

IV

25 Performance Evaluation Of Models 23

25 Summary 24

CHAPTER 3 METHODOLOGY

31 Introduction 26

32 Data Collection 28

33 Preparation Of Data 29

34 Fourier Series 31

35 Modeling Procedures 35

36 Summary 41

CHAPTER 4 RESULTS AND ANALYSIS

41 Introduction 42

42 Analysis Of Data 42

43 Simulation Results 45

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

51 Overview 49 i

52 Conclusions 50

53 Recommendations For Future Study 50

REFERENCES

APPENDICES

v

LIST OF FIGURES

Title Page

Figure 11 HadCM3 PRECIS simulations of annual raindays for Malaysia 3

Figure 12 HadCM3 PRECIS simu1ations of annual and DJF seasonal 3

precipitation anomaly for Malaysia

Figure 13 Sungai Sarawak basin area and location of hydrological stations 8

Figure 14 Map of SCORE 10

Figure 15 Projected flow 11

Figure 21 Hydrological model development 15

Figure 22 Observed and fitted mean rainy day 21

Figure 23 Annual and average rainfall in Iran 23

Figure 31 Research framework 27

Figure 32 Annual rainfall periodic function of case study 36

Figure 33 Fitting N-term Harmonic Series simulation procedures 38

Figure 34 Fitting N-term Harmonic Series 39

Figure 35 Setting the harmonic series 39

Figure 36 Coefficients of Fourier Series 40

Figure 37 RMS andx2 40 ~

Figure 38 Output 41

Figure 41 Consistency check - Sembam 43

Figure 42 Consistency check - Padawan 43

Figure 43 Consistency check - Sungai China 43

Figure 44 Simulation output for 2003 to 2011 46

VI

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

Pu ut Khidmu MakJumat Ak demik I 1 VSIA SARAWAK

TABLE OF CONTENT

CONTENT Page

ACKNOWLEDGEMENT

ABSTRACT 11

ABSTRAK 1lI

LIST OF FIGURES vii

LIST OF TABLES VllI

LIST OF ABBREVIA nONS IX

CHAPTER 1 INTRODUCTION

11 General

12 Problem Statement 4

13 Objectives 5

14 Scope Of Study 6

15 Significance Of Study 9

16 Report Outline 12

CHAPTER 2 LITERATURE REVIEW

21 Introduction 13

22 Hydrological Model 14

23 Preceding Study 16

24 Fourier Series 19

-

IV

25 Performance Evaluation Of Models 23

25 Summary 24

CHAPTER 3 METHODOLOGY

31 Introduction 26

32 Data Collection 28

33 Preparation Of Data 29

34 Fourier Series 31

35 Modeling Procedures 35

36 Summary 41

CHAPTER 4 RESULTS AND ANALYSIS

41 Introduction 42

42 Analysis Of Data 42

43 Simulation Results 45

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

51 Overview 49 i

52 Conclusions 50

53 Recommendations For Future Study 50

REFERENCES

APPENDICES

v

LIST OF FIGURES

Title Page

Figure 11 HadCM3 PRECIS simulations of annual raindays for Malaysia 3

Figure 12 HadCM3 PRECIS simu1ations of annual and DJF seasonal 3

precipitation anomaly for Malaysia

Figure 13 Sungai Sarawak basin area and location of hydrological stations 8

Figure 14 Map of SCORE 10

Figure 15 Projected flow 11

Figure 21 Hydrological model development 15

Figure 22 Observed and fitted mean rainy day 21

Figure 23 Annual and average rainfall in Iran 23

Figure 31 Research framework 27

Figure 32 Annual rainfall periodic function of case study 36

Figure 33 Fitting N-term Harmonic Series simulation procedures 38

Figure 34 Fitting N-term Harmonic Series 39

Figure 35 Setting the harmonic series 39

Figure 36 Coefficients of Fourier Series 40

Figure 37 RMS andx2 40 ~

Figure 38 Output 41

Figure 41 Consistency check - Sembam 43

Figure 42 Consistency check - Padawan 43

Figure 43 Consistency check - Sungai China 43

Figure 44 Simulation output for 2003 to 2011 46

VI

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

25 Performance Evaluation Of Models 23

25 Summary 24

CHAPTER 3 METHODOLOGY

31 Introduction 26

32 Data Collection 28

33 Preparation Of Data 29

34 Fourier Series 31

35 Modeling Procedures 35

36 Summary 41

CHAPTER 4 RESULTS AND ANALYSIS

41 Introduction 42

42 Analysis Of Data 42

43 Simulation Results 45

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

51 Overview 49 i

52 Conclusions 50

53 Recommendations For Future Study 50

REFERENCES

APPENDICES

v

LIST OF FIGURES

Title Page

Figure 11 HadCM3 PRECIS simulations of annual raindays for Malaysia 3

Figure 12 HadCM3 PRECIS simu1ations of annual and DJF seasonal 3

precipitation anomaly for Malaysia

Figure 13 Sungai Sarawak basin area and location of hydrological stations 8

Figure 14 Map of SCORE 10

Figure 15 Projected flow 11

Figure 21 Hydrological model development 15

Figure 22 Observed and fitted mean rainy day 21

Figure 23 Annual and average rainfall in Iran 23

Figure 31 Research framework 27

Figure 32 Annual rainfall periodic function of case study 36

Figure 33 Fitting N-term Harmonic Series simulation procedures 38

Figure 34 Fitting N-term Harmonic Series 39

Figure 35 Setting the harmonic series 39

Figure 36 Coefficients of Fourier Series 40

Figure 37 RMS andx2 40 ~

Figure 38 Output 41

Figure 41 Consistency check - Sembam 43

Figure 42 Consistency check - Padawan 43

Figure 43 Consistency check - Sungai China 43

Figure 44 Simulation output for 2003 to 2011 46

VI

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

LIST OF FIGURES

Title Page

Figure 11 HadCM3 PRECIS simulations of annual raindays for Malaysia 3

Figure 12 HadCM3 PRECIS simu1ations of annual and DJF seasonal 3

precipitation anomaly for Malaysia

Figure 13 Sungai Sarawak basin area and location of hydrological stations 8

Figure 14 Map of SCORE 10

Figure 15 Projected flow 11

Figure 21 Hydrological model development 15

Figure 22 Observed and fitted mean rainy day 21

Figure 23 Annual and average rainfall in Iran 23

Figure 31 Research framework 27

Figure 32 Annual rainfall periodic function of case study 36

Figure 33 Fitting N-term Harmonic Series simulation procedures 38

Figure 34 Fitting N-term Harmonic Series 39

Figure 35 Setting the harmonic series 39

Figure 36 Coefficients of Fourier Series 40

Figure 37 RMS andx2 40 ~

Figure 38 Output 41

Figure 41 Consistency check - Sembam 43

Figure 42 Consistency check - Padawan 43

Figure 43 Consistency check - Sungai China 43

Figure 44 Simulation output for 2003 to 2011 46

VI

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

LIST OF TABLES

Table Description Page

Table 11 ResHCM-PM PRECIS hydro climatic observed and projections in 2

Malaysia

Table 21 Summary of statistics criteria performance evaluation of models 23

Table 22 FS coefficients and NSRP parameters 24

Table 31 Selected hydrological stations 28

Table 41 Polygon area and weightage by Thiessen-Polygon Method 44

Table 42 Descri pti ve statistics 45

Table 43 RMSE and x2 for n = 2 3 and 4 47

Table 44 Simulation result and observed rainfall 47

Vll

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

LIST OF APPENDICES

Appendices Description

APPENDIX A Monthly data

APPENDIX B Adequacy check of rain gauge stations

APPENDIX C Estimation of missing rainfall data - Normal Ratio Method

APPENDIX D Mean areal precipitation using Thiessen Polygon Method

APPENDIX E Fitting N-term Harmonic Series simulation output

VIII

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

LIST OF ABBREVIATIONS

Abbreviations Descriptions

N Number of optimal stations

Coefficient of variation

Allowable degree of error

Precipitation of station

M Number of neighboring stations

Monthly normal of station

Corrected precipitation

Corrected slope of the double-mass curve

Original slope of the double mass-curve

IX

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

CHAPTERl

INTRODUCTION

11 General

Recent reports on climate change have stirred global worries The regional climate

projects that the mean sea level temperature and rainfall variability in all regions will

increase in the future Precipitation in the southern part and most part of Southeast Asia

will likely increase in boreal winter and summer Christensen et a1 (2007) predicts

extreme rainfall and winds associated with tropical cyclones will likely to increase with

an increase in the frequency of intense precipitation events

In the Malaysia Second National Communication (NC2) to the United Nation

Frameworks Convection on Climate Change (UNFCC) has revealed that there is an

increase in the annual mean surface temperature to 06 degc - 12 degc per year based on 40shy

year observations Rainfall intensity observations from the year 2000 to 2007 are found to

have exceeded the highest recorded rainfall intensity in 1971 to 1980 that was previously

reported During the same observation period the annual maximum rainfall intensity has

increased by 17 and 29 for 1 hour and 3 hour durations respectively The mean sea

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

level recorded at Tanjung Piai Johor also indicated an increase of rate as much as 13

mmJ year in the observed year 1986 to 2006 (N C2 2011) The behavior of the results is

found to be consistent with the findings of the regional climate projections

In concern with the climate change particularly in Malaysia two models were

used to evaluate the hydro climatic projections for the year 2050 and 2099 The models

are known as Regional Hydro - Climate Model for Peninsular Malaysia (ResHCM-PM)

and Providing Regional Climater for Impact Studies (PRECIS) Both models were used

for hydro climatic projections in the West Malaysia however only PRECIS was used for

hydro climatic projections in the East Malaysia The findings for both observed and

projected climate change throughout the country is summarized in Table 11

Table 1 1 ResHCM-PM PRECIS hydro climatic observed and projections in Malaysia (NC22011)

Observed Projected by 2050

Temperature 06 Uc - 12 Uc per 50 years (1969 - 2009)

15 vc - 2 vc increase

Rainfall (amount) No appreciable difference (-) 5 to (+) 9 change in regions within PM

(-) 6 to (+) 11 change in reglOns within Sabah and Sarawak

Rainfall intensmiddot y Increased by 17 for 1 hour duration and 29 for 3hour duration (2000-2007) compared to 1971-1980)

Increase in extremes within wet cycles

Increase in frequency of extreme weather

Sea level rise (SLR) 13 mmlyr (1986 - 2006 Tanjung Piai Johor)

05 m rise (Global high worst case at 10 mmlyr)

2

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

LIlA

Figure 1 1 HadCM3 PRECIS simulations of annual rain days for Malaysia (Sammathuria et al 2010)

DeC1ATO

rl- LunULUIIA

uluI

Figure 1 2 HadCM3 PRECIS simulations of annual and DJF seasonal precipitation anomaly for Malaysia (Sammathuria et al 2010)

Sammathuria et al (2010) have used HadCMe PRECIS to project the annual

precipitation anomaly December-January-February (DJF) seasonal precipitation anomaly

and annual rain days projections for the year 2000 to 2099 Results of the simulation are

as depicted in Figure 11 and Figure 12 The significant interdecadal variation detected

3

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

in all simulations suggested that there would be a long-term extended dry spells Sarawak

is predicted to experience negative annual precipitation for forty years

Both regional and national reports have suggested there is a change in the rainfall

pattern whereby the intensity of precipitation events will increase Christensen et al

(2007) stated that the regional quantitative estimations of precipitation change are

difficult to obtain as they are limited to uncertainties in the sources and studies should be

done on a smaller scale While Sammathuria et al (2010) suggested that Sarawak will

experience forty years of drought in their projection up to the year 2099 Therefore

studies in enhancing the ability for rainfall forecasting models in capturing the change of

climate and its effects on the rainfall patterns are greatly needed for future guidelines and

preparations

12 Problem Statement

The study of rainfall forecasting plays an important role to a country such as

Malaysia where the rain is abundant Malaysia receives rainfall from 2000 mm to 4000

mm annually where it is greatly influenced by two monsoon periods in November to

March and May to September The state of Sarawak is well known for its long and wide

rivers and rivers have always been the main transportation and still are in certain remote

areas Numerous activities such as commercial industrial and residential can always be

found in the vicinity of the rivers The activities have started since decades ago and still

continue to grow and spatially expanding through times providing incomes ranging from

4

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

--~--111----------p~ut1~hidmat Maklumat Akademik ~Ill MALAYSIA SARAWA)

small fanners to the largest corporations Unfortunately these areas are expected to

experience frequent flood events as well as possible receding water level in rivers based

on the findings of previous studies If the projections are accurate the productivity of

these activities will be reduced hence in a longer tenn may affect the economy of the

state as whole as well

Therefore there is an urgent need for existing knowledge on rainfall behavior to be

revised as effects of climate change with the intention that the state can fully utilize the

favorable conditions and make scientific based decisions in the future Further study in

rainfall forecasting focusing on the state of Sarawak as suggested lby Christensen et al

(2207) is indeed very crucial to improve the estimation accuracy for long-tenn rainfall

prediction Long-tenn prediction is important for planning and management in various

sectors where rain is considered as a major driving factor such as agriculture and water

resources

13 Objective

Fourier Series has been well accepted as a tool that has improved the result of

hydrological modeling and reduces complex parameters analysis for simulation purposes

Recent study by Rostam Afshar and Fahmi (2012) reveals the ability of Fourier Series to

simulate long-tenn rainfall up to 300 years is viewed as an important finding in the study

of rainfall forecast For this reason the main goal of the study is to forecast rainfall for

Sungai Sarawak basin and the objectives are

5

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

1 To screen missing rainfall data

~

2 To check on the adequacy of the number of selected rain gauge station

3 To check on the consistency of the rainfall record

4 To estimate the mean areal rainfall of the Sg Sarawak basin

5 To model the rainfall simulation using mathematical modeling le Fourier

Series

6 To verify the simulation result using statistical analysis ie Root Mean Square

and Chi-Square

14 Scope of Study

The selected study area was Sungai Sarawak basin as depicted in Figure 13 The

basin is currently under the management of the Sarawak Department of Drainage (DID)

Daily rainfall data was obtained from DID for eight hydrological stations Data was

prepared and analyzed as monthly rainfall data for modeling purpose The method of

modeling was using Fourier Series and results were statistically verified for one year

observed data

The basin consists of 49 hydrological stations of which 37 are rain gauge stations

The basin area is approximately 2 459 km2 with river length of 120 km Originating from

Kapuas Mountains Sg Sarawak that consists of two main tributaries ie Sg Sarawak

6

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

Kiri and Sg Sarawak Kanan runs through the city before exiting to South China Sea The

river is lively with numerous activities along the river Improvement in the rainfall

forecast study will benefit the state as well as public by proper planning and mitigation of

water resources

7

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

17

J

15

SUNGAI 8ARAlJAX BASIN 1shy CAL

Figure 13 Sg Sarawak basin area and location of hydrological stations (DID)

8

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

15 Significance of Study

Rain is considered to be an important hydrological component in the study of

water resources in general Malaysia is predicted to have adequate water resources

between the years 2025 to 2050 however during dry season urban areas are expected to

experience water disruption since water supply will be greatly shared among many

sectors such as domestic and industries The increase in population and rapid

development in various sectors will give rise to the demand of water significantly which

leads to a draw down in water supply reservoirs In 2012 the water level in Sungai

Selangor dam was reported has dropped and the capacity of the dam has decreased as

much as 50 (Mahmood 2012) In the same year the rivers water level in Kota Tinggi

Kluang Mersing and Muar districts were also reported have slightly dropped due to the

hot weather which caused SAl holdings to be on alert ensuring there was not disruption

of water supply at the Sungai Sayong water treatment Kota Tinggi SAl holdings is

currently in charge for the water treatment and distribution of treated water in lohor

It is to the authors point of view that the same scenarios will occur here in

Sarawak Sarawak in its long term planning via series of dams construction has aim to

increase the industrial activities within the state to enhance economy growth through

hydropower Larger areas allocated for industries would definitely lead to significant

increase in water demand Under the Master Plan of Sarawak Corridor of Renewable I

Energy (SCORE) to connect to the industries that are located along the coastal twelve

hydroelectric dams of 20 000 MW capacity needed to be built for a distance

approximately 320 km from Tanjung Manis to Samalaju (Figure 14) The area covered

is half ofthe size of the state 70 709 km2 (Sovacool and Bulan 2012)

9

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

- Po ~ upr tornlklf bull l(Cn(lll (M 1I111 lluIII power

bull H~dlo poIcnllai III I 1(101 D Rm 0001

Po(I dtlmlld ((110 ~1I1m110n n~ rClllo1l S((1R MII

bull II n l 1gt1 bull ~ I of I~ hydr(l II

o r~ middotInll IIhln Hil i 11 111 ~

bull ~ IXJO~I (lOfallinl bull SmiddotOOO GllCD(I~middot

B 1111 1

lu ail -

~ _ ___u

bull Figure 14 Map of SCORE (Sarawak Energy Berhad 2013)

Agricultural production depends very much on the temperature and rainfall

variability Prolong drought or seasonal rainfall will hinder the productivity of the sector

The long duration of drought will disrupt the irrigation of water and may stop any

planting activity while flood will damage the crops within the affected areas The study of

rainfall estimation is viewed to be able to minimize the damages and take advantage the

favorable behavior of the climate for agricultural poundectors through proper planning and

mitigation

In addition to the 2011 climate change projection for Malaysia one of the findings

that should be taken seriously is the prediction of increase in the flood frequency The rise

of mean sea level together with the increase in the rainfall intensity NC2 (2011)

10

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

projected that the existing flood affected areas will experience an Increase In the

frequency of flood event while present unaffected areas will likely experience flood

(Figure 15) Located at the vicinity of estuary a flood prone area at present the city of

Kuching is viewed to be more vulnerable in the future based on the projections It is to the

authors point of view that this study will benefit the state of Sarawak very much in its

future planning and mitigation

NAHRIMs RegHCM-SS KEDAMAIAN ( 1 J P amp FLOODS )

Projected Flow 2040-2050 2090middot2100 Low Flow (mls) 175f(340) 3181(340)

High Flow (mls) 218 9i 1008) 1484 ( 10080)

amp I bull 1Lltsn I I1middot-1UG1 I 1I 1Jn11 ~1 - ~ ~ E r ~ _ ~l ~

8 ~

I

~L tthul out

middot ~~ middotft rr 1 1t

~ uill1 I II )ab I

Ed ~rmiddotL IIbIIqJ

TnL r

J

FLOODSSARAWAK R (FLOODS ) CJ 2040 middot2050 2090 middot21 00

Low Flow(mls) 29 1 405 6 16i (405) High Flow(mls) 8942( 9842) 13391(9842)

Figure 15 Projected flow(NC2 2011)

11

future study

16 Report Outline

The report consists of five main chapters Chapter 1 gives the overVIew of study

background A problem statement is discussed where from there the objective of the study

is detennined The breadth and depth of the study is given in the scope of study and the

significance of conducting the study

Chapter 2 is the literature review mainly focusing on the study development of rainfall

forecasting especially on abstract model the development of hydrological modeling the

limitations as well as the improvements and the challenges often faced by researchers

Chapter 3 outlines the procedures done in carrying out the study eg preparation of data

construction of model and methods of verification

Chapter 4 presents the results and discussions of the study inclusive of the evaluation on

whether the model was able to achieve the objective of the study and the limitations ofthe

study

Chapter 5 generally summarized the study based on the results and analysis Conclusion

was made whether the study has achieved its main purpose and recommendations for

12

CHAPTER 2

LITERATURE REVIEW

21 General

The tudy of rainfall forecast is crucial to a country such as Malaysia where rainfall

is received in abundant annually Every year there is always news on flood events taking

place throughout the country In addition having agricultural activity as one of the main

contributor to the economy growth of the country there is an even greater need to

understand the occurrence of future rainfall for planning and management for both dry and

wet season The country would benefit by taking advantage of the favorable conditions by

baving a guiding standard in increasing crop production for reservoir operation and

flooding prevention Simultaneously mitigate the adverse impacts of the rainfall during

extreme events of wet and dry season The sustainability of water resources in some part

of the country is also at question where recent reports on the drop in the water storage

have cause worries among the stakeholders as they have to find other source of water for

future usage

Malaysia is predicted to experience wet and dry season to the extreme in 50 years

With the combination of the sea level increment and increase in rainfall intensity floods

are expected to occur in low-lying areas especially coastal areas Sarawak having the

13

largest river in Malaysia where having high population concentration can be observed

along the river there is a tendency for these areas to be frequently inundated in the future

Rainfall forecasts can be a great tool in making scientifically based decisions on long-term

planning and management of water resources therefore minimizing any possible hardship

incurred to stakeholders

22 Hydrological Model

Generally the development of hydrologic models can be constructed with

guidelines such as in Figure 21 Chow et al (1988) stated that the model could be

classified according to the way they transform the input to output Deterministic models

transform inputs to outputs based on the deterministic relationship Models that work on

such principle are also known as physical or conceptual models Conceptual model is

designed based on the knowledge and characteristics of the basin normally for a smallshy

scale basin It assembles component equations that represent the hydrologic processes of

the basin However physical model is not feasible in the study of rainfall forecasting

because it requires significant calibration data to reasoning rainfall Furthennore the

salculations of rainfall volume will require sophisticated mathematical tools in addition to

solve the thermodynamic equation Despite that the model can be improved with the

development of mixed stochastic detenninistic models such as simplified meteorological

models on a basin scale (Burlando et al 1996 Wei 2008 Luk et al 2001)

14

CHAPTER 2

LITERATURE REVIEW

21 General

The tudy of rainfall forecast is crucial to a country such as Malaysia where rainfall

is received in abundant annually Every year there is always news on flood events taking

place throughout the country In addition having agricultural activity as one of the main

contributor to the economy growth of the country there is an even greater need to

understand the occurrence of future rainfall for planning and management for both dry and

wet season The country would benefit by taking advantage of the favorable conditions by

baving a guiding standard in increasing crop production for reservoir operation and

flooding prevention Simultaneously mitigate the adverse impacts of the rainfall during

extreme events of wet and dry season The sustainability of water resources in some part

of the country is also at question where recent reports on the drop in the water storage

have cause worries among the stakeholders as they have to find other source of water for

future usage

Malaysia is predicted to experience wet and dry season to the extreme in 50 years

With the combination of the sea level increment and increase in rainfall intensity floods

are expected to occur in low-lying areas especially coastal areas Sarawak having the

13

largest river in Malaysia where having high population concentration can be observed

along the river there is a tendency for these areas to be frequently inundated in the future

Rainfall forecasts can be a great tool in making scientifically based decisions on long-term

planning and management of water resources therefore minimizing any possible hardship

incurred to stakeholders

22 Hydrological Model

Generally the development of hydrologic models can be constructed with

guidelines such as in Figure 21 Chow et al (1988) stated that the model could be

classified according to the way they transform the input to output Deterministic models

transform inputs to outputs based on the deterministic relationship Models that work on

such principle are also known as physical or conceptual models Conceptual model is

designed based on the knowledge and characteristics of the basin normally for a smallshy

scale basin It assembles component equations that represent the hydrologic processes of

the basin However physical model is not feasible in the study of rainfall forecasting

because it requires significant calibration data to reasoning rainfall Furthennore the

salculations of rainfall volume will require sophisticated mathematical tools in addition to

solve the thermodynamic equation Despite that the model can be improved with the

development of mixed stochastic detenninistic models such as simplified meteorological

models on a basin scale (Burlando et al 1996 Wei 2008 Luk et al 2001)

14

largest river in Malaysia where having high population concentration can be observed

along the river there is a tendency for these areas to be frequently inundated in the future

Rainfall forecasts can be a great tool in making scientifically based decisions on long-term

planning and management of water resources therefore minimizing any possible hardship

incurred to stakeholders

22 Hydrological Model

Generally the development of hydrologic models can be constructed with

guidelines such as in Figure 21 Chow et al (1988) stated that the model could be

classified according to the way they transform the input to output Deterministic models

transform inputs to outputs based on the deterministic relationship Models that work on

such principle are also known as physical or conceptual models Conceptual model is

designed based on the knowledge and characteristics of the basin normally for a smallshy

scale basin It assembles component equations that represent the hydrologic processes of

the basin However physical model is not feasible in the study of rainfall forecasting

because it requires significant calibration data to reasoning rainfall Furthennore the

salculations of rainfall volume will require sophisticated mathematical tools in addition to

solve the thermodynamic equation Despite that the model can be improved with the

development of mixed stochastic detenninistic models such as simplified meteorological

models on a basin scale (Burlando et al 1996 Wei 2008 Luk et al 2001)

14