UNIVERSITI PUTRA MALAYSIA

ANALYSIS AND FIELD STUDIES OF SALTWATER INTRUSION IN A COASTAL AQUIFER : A CASE OF BACHOK, KELANTAN

RUSLAN HASSAN

FK 2001 15

ANALYSIS AND FIELD STUDIES OF SALTWATER INTRUSION IN A COASTAL AQUIFER: A CASE OF BACHOK, KELANTAN

By

RUSLAN HASSAN

Dissertation Submitted in Fulfilment of the Requirement for the Degree of Doctor of Philosophy in the Faculty of Engineering

Universiti Putra Malaysia

October 2001

DEDICATION

I wish to dedicate this work to the poor farmers of Bachok, Ke/antan, who simply refused to give up.

II

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirements for the degree of Doctor of Philosophy

ANALYSIS AND FIELD STUDIES OF SALTWATER INTRUSION IN A COASTAL AQUIFER: A CASE OF BACHOK, KELANTAN

By

RUSLAN HASSAN

October 2001

Chairman: Dato' Prof. Ir. Dr. Muhamad Zohadie Bardaie

Faculty : Engineering

This dissertation deals with the extent of saltwater/chloride distribution in

a two-layered coastal aquifer. The area chosen for the study is located in the Mukim

of Bachok, Kelantan which covers an area of 72 km2 about 20 km South East of Kota

Bharu. The area mainly consists of a large flat plain, with soils belonging to the Bris

complex (82 - 99% sand) and drained mainly by the meandering Kemasin River and

its tributaries. Groundwater contamination by chloride has become a threat to this

area, economically and to health. Chloride concentrations have exceeded their

permissible limits thereby limiting their eventual uses in tobacco farming and as

drinking water. The objectives of this study are therefore to analyse the saltwater

intrusion and contamination in the area; to obtain the necessary understanding of the

chloride movement and distribution; and finally, to ascertain and make reasonable

predictions as to the future contamination of the area by the saltwater.

IJl

The approach taken was two-folds, namely to investigate the chloride

distribution in the upper aquifer which is mainly utilized for tobacco farming and to

analyse the saltwater intrusion using sharp interface and dispersive approaches in the

lower aquifer. The analysis on the extent of chloride distribution in the upper aquifer

was based on the field investigation covering a period between 1 991 - 1995. The field

studies were carried out by comprehensive data collection on the upper aquifer for a

period of four (4) years which preceded the one (1 ) year MARDI study. Field studies

on the lower aquifer were carried out for a period of two (2) years (1994 and 1995).

The analysis on the Bachok coastal aquifer groundwater systems was

done by means of the Regional Groundwater model. The middle stretch of the

Kampong Cap transect (DDMl -5) was studied further using the data obtained from

Pfeiffer study and the two-zone model. The latter model made use of the discrete

space-discrete time approach. To understand the flow paths within the aquifer, an

analogue model and PSpice were used.. The parameters thus determined were

incorporated in the Regional Groundwater model. Chloride distribution for the upper

aquifer was then analysed. As for the upper aquifer, there was an increase in the

content of chloride concentration compared to the earlier MARDI study despite the

seasonal flushing of the saline water. The chloride increased with higher precipitation

(November and December annually) in the flood plains, which was opposite to the

long held theory that dilution would decrease the concentration.

The cross-section P-Q which had the most data and better defined than the

other cross-sections was chosen for simulating the saline intrusion using SUTRA

model. A single unified aquifer was chosen for the purpose since, the aquifer is

IV

hydraulically connected at this cross-section. Cross-sectional intrusion analysis was

accomplished in two stages. In the first stage, a steady- state calibration procedure

was performed to obtain a match between the theoretical Ghyben-Herzberg position

of the interface with that of the computed one and the observed field values. In the

second stage, the transient behaviour of the interface was analysed using the dry

period and discharge (production wells) and average recharge rates plus the discharge.

It was found that for the aquifer system of Bachok, the groundwater in the

lower aquifer is being contaminated by saline water. The saltwater wedge had reached

a distance of 6 km (DDM4) from the sea. The chloride concentrations had exceeded

1000 mgIL for a 10-months period in 1995. The degree and extent of saline intrusion

depends on the season and was obviously furthest inland during the dry season. As a

long-term prediction, it is envisaged that within 25 years from 1994, at the present

withdrawal rate of 45,000 gallons per day, the chloride concentration at Kg. Cap will

attain a value of 103 mg/L (within the 0. 1 isochlor line). The dispersive approach was

more applicable here rather than the sharp interface. It described with reasonable

accuracy the movement of the interface of the P-Q transection in the lower aquifer,

with the hydraulic connection existing between the upper and lower aquifer. It is

recommended that for the tobacco farming, the activity should be limited to an area,

one (1) km away from both the river and the sea. For saltwater intrusion control in

this study area, it is proposed that the water withdrawal be regulated, producing wells

be redistributed and monitoring system (including the use of SUTRA) be incorporated

in such a way that saltwater intrusion remains in equilibrium while developing the

aquifer to its maximum possible yield.

v

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Doktor Falsafah

ANALISIS DAN KAJIAN LAPANGAN SUSUPAN AIR MASIN KE SUATU AKUIFER BERHAMPIRAN PANTAI : KAJlAN KES DI BACHOK,

KELANTAN

Oleh

RUSLAN HASSAN

Oktober 2001

Pengerusi: Dato' Prof. Ir. Dr. Muhamad Zohadie Bardaie

Fakulti : Kejuruteraan

Disertasi ini menangani setakat mana agihan kloridalair masin di dalam akuifer

yang berlapisan dua berhampiran dengan sebuah pantai. Kawasan kajian yang dipilih

terletak dalam Mukim Bachok, Kelantan yang luasnya adalah 72 km2, dan jauhnya

lebih kurang 20 km di Selatan hala Timur Kota Bharu. Kawasan ini terdiri daripada

tanah rata yang luas yang tanahnya tergolong daripada jenis kompleks Beris (pasir 82

- 99%) dan disalirkan oleh Sungai Kemasin dan alur-alur yang berliku-liku.

Pencemaran oleh kemasukan air masin mengakibatkan kesan buruk kepada kegiatan

tanaman tembakau dan kesihatan. Pada kebanyakan tempat, nilai klorida melebihi

hadnya yang memberi kesan kepada penggunaannya. Objektif kajian ini meliputi

menganalisis kedudukan kemasukan air masin, memahami pergerakannya dan

kemudian membuat jangkaan potensi penerobosannya pada mas a akan datang.

vi

Pendekatan yang diambil ialah mengkaji akuifer atas yang almya

digunakan untuk tanaman tembakau kemudian menganalisa kemasukan air masin ke

dalam akuifer bawah dengan pendekatan permukaan antara jelas dan dispersif.. Kajian

di akuifer atas meliputi kajian di tapak di antara tahun 1992 - 1995. Bagi kajian

akuifer di bawah, data dikumpul selama 2 tahun ( 1994 dan 1995).

Penganalisisan sistem air tanah di kawasan pantai Bachok dilakukan

dengan menggunakan model air tanah wilayah ('regional ground water model').

Bahagian tengah Kampong Cap (DDMl -S) dipilih untuk kajian lanjutan dengan

menggunakan hasil kajian Pfeiffer dan model dua-zon. Model dua zon menggunakan

pendekatan ruang diskrit-ruang masa. Untuk memahami laluan air di keratan pilihan

ini model analog kemudiannya digunakan. Nilai yang didapati digunakan batik dalam

model wilayah. Agihan klorida bagi akuifer dikaji dan ianya menunjukkan

peningkatan nilai klorida berbanding dengan kajian MARDI yang terdahulu.

Kandungan klorida didapati tinggi bila terdapatnya banjir dan ini berbeza dengan

pendapat sebelum ini yang hujan akan mencairkan kandungan klorida.

Keratan P-Q dipilih untuk kajian simulasi dengan menggunakan model

SUTRA kerana mempunyai data yang mencukupi berbanding dengan yang lain.

Anggapan suatu akuifer tunggal digunakan dalam analisis kerana terdapat kaitan

hidraul antara akuifer atas dan bawah pada keratan ini. Analisis kemasukan air masin

di keratan rentas ini disempumakan dengan membuat dua langkah. Pertama, prosedur

kalibrasi keadaan stabil didapati dengan menggunakan kedudukan Ghyben-Herzberg

dan data yang diukur di tapak. Kedua, kelakuan transien permukaan antara dianalisa

Vll

dengan menggunakan kadar musim kering dan pengambilan air (kadar alir keluar) dan

purata kadar recaj dengan kadaralir.

Adalah didapati bagi sistem akuifer di Bachok, aimya telah dicemari oleh

air masin. Air masin telah sampai di takat 6 km dari pantai iaitu di DDM4. Kepekatan

klorida pada jangka masa 10 bulan dalam setahun (1995) telah melebihi 1000 mg/L.

Tahap dan sejauh mana penorobosan air masin bergantung kepada musim dan adalah

lebih jauh ke darat dalam musim kering. Dalam jangkamasa yang panjang, adalah

dianggarkan dalam masa 25 tahun (daripada 1994), pada kadar pengambilan air

sekarang iaitu 45,000 gelen sehari, kepekatan klorida di Kg. Cap akan mencapai 103

mg/L (dalam lingkungan 0.1 isoklor). Pendekatan dispersif lebih terpakai di kawasan

ini berbanding dengan pendekatan permukaan antara tepat ('sharp-interface').

Pendekatan dispersif menunjukkan dengan agak tepat, pergerakan permukaan antara

di keratan P-Q bilamana terdapat kaitan hidraul antara akuifer atas dan bawah.

Berdasarkan hasil kajian, beberapa langkah dicadangkan untuk

menangani masalah klorida. Tanaman tembakau mestilah dijalankan pada jarak satu

(1) km daripada sungai Kemasin dan juga pantai. Bagi kawalan kemasukan air masin

di akuifer bawah, adalah dicadangkan, bahawa pendekatan yang sebaik-baiknya ialah

dengan mengatur ekstraksi air daripada akuifer, diagih semula lokasi takat

pengeluaran air dan melakukan pemantauan yang rapi dan terkini (termasuk

menggunakan model SUTRA ini). Langkah ini adalah untuk memastikan

keseimbangan permukaan antara, bilamana akuifer hendak dimajukan ke tahap

pengeluaran semaksima mungkin.

viii

ACKNOWLEDGEMENTS

In the name of ALLAH Most Beneficient and Most Merciful, I would like to extend my sincerest appreciation to the following:

Professor Dato' Dr. Ir. Muhamad Zohadie Bardaie, Associate Professor Dr. Salim Said and Dr Aziz Zakaria for making this undertaking possible especially with the IRPA 1-07-05-0609 (J03) fund,

En. Mohammud Che Husain of MARDI, Kubang Keranji, Kelantan who is ever willing to help,

Rashid Bacik and Mohd Nazan Awang of the Geology Department,

En. Hamadi Che Harun, the Kelantan State Geology Director,

The late Associate Professor Dr. Ismail Md. Noor for advising me to take up an area in Bachok, Kelantan as my case study,

Professor Ken Rushton, Ph.D, DSc., for supervising my work at Birmingham University, UK,

Dr. John P Watts, Assistant Representative of the British Council, Kuala Lumpur for granting me the 1992 High Commissioner's Award,

En. Bakhtiar Lubis and Amiruddin Hashim who have made my stay in Birmingham, UK bearable,

En. Kamkah Ahmad of JKR, Bachok, who never fails to assist me,

Wan Azman, Hanafi and Yunus who have helped in the data collection, and

last but not least my wife, Nadirah Yahya who is very supportive and the six children who have endured my intermittent but sometimes long absence from home since embarking on this study.

ix

I certify that an Examination Committee has met on 8th October 2001 to conduct the final examination of Ruslan b. Hassan on his Doctor of Philosophy thesis entitled "Analysis and Field Studies of Salt Water Intrusion in a Coastal Aquifer: A Case of Bachok, Kelantan" in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommended that the Candidate be awarded the relevant degree. The Committee Members for the candidate are as follows:

Mohd Amin Mohd Soom, Ph.D. Associate Professor F acuIty of Engineering Universiti Putra Malaysia (Chairman)

Muhamad Zohadie Bardaie, Ph.D. Professor and Vice-Cancellor Faculty of Engineering Universiti Putra Malaysia (Member)

Salim Said, Ph.D. Associate Professor, Faculty of Engineering Universiti Putra Malaysia (Member)

Aziz Zakaria, Ph.D. Lecturer Faculty of Engineering Universiti Putra Malaysia (Member)

Md. Noor Salleh, Ph.D. Professor and Vice-Cancellor, Universiti Pendidikan Sultan Idris (UPSI) Tanjung Malim, Perak (Independent Examiner)

Mohd Ghazali Mohayidin, Ph.D. Professor! Deputy Dean of Graduate School,

Universiti Putra Malaysia

x

Date: 24th October 2001

This Thesis submitted to the Senate ofUniversiti Putra Malaysia has been accepted as fulfilment of the requirement for the degree of Doctor of Philosophy.

xi

Aini Ideris, Ph.D. Professor Dean of Graduate School, Universiti Putra Malaysia

Date: 1 3 Dte 2001

DECLARATION

I hereby declare that the thesis is based on my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions.

Ruslan Hassan

Date: 24th October 2001

xii

TABLE OF CONTENTS

DEDICATION ABSTRACT ABSTRAK ACKNOWLEDGEMENTS APPROVAL SHEETS DECLARATION FORM T ABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF PLATES LIST OF SYMBOLS AND ABBREVIATIONS

CHAPTER

I GENERAL INTRODUCTION Concerns on Saltwater Intrusion in Peninsular Malaysia Modelling Groundwater Systems Statement of Problem Objectives Scope Outline of the work

II BACKGROUND AND LITERATURE REVIEW Salt Water Intrusion Phenomenon Methods of Solving Saltwater Intrusion and Related Ground Water Problems

Physical Models Mathematical Models

Analytical Models Numerical Models Selection of Approach to be Used in the Present Investigation

III APPROACHES USED IN SALTWATER INTRUSION Ghyben-Herzberg Equation Sharp-Interface Approach

Governing equations Mass Balance Momentum Balance Three-Dimensional equations Vertical Integration Surface Conditions

xiii

Page

U 111 VI IX

X XU

X111 XVI XIX

XXlll

XXIV

1 2 3 4 5 6 6

7 7

10

1 1 1 2 1 3 14 16

18 1 8 20

22 22 22 23 26

Final equations Dispersive Approach

Two-Dimensional Miscible Transport Models Steady-State Conditions Transient or Unsteady State conditions

SUTRA Model Physical-Mathematical Basis of SUTRA Simulation The Fluid Flow and Flow Properties Fluid Mass Balance Simulation Work

IV HYDROGEOLOGICAL SETTING AND ANALYSES OF THE STUDY AREA Location of the Study Area Soil Characteristics Geology and Hydrology Hydrogeochemical Character and Groundwater Facies

Recognition of Seawater in Groundwater Hydrogeology

Aquifer Characteristics Determination of Permeability and Transmissivity Transmissivity by Means of Theis and Jacob Methods Pumping Test Analysis Application of the Two-Zone Model Representation of the Flow System at Kg. Cap (Test WeIl l )

Recharge Assessments Water Quality of Groundwater Kemasin River Water Quality

V INVESTIGATIONS ON WATER AND CHLORIDE LEVELS Field Investigation Set-up Groundwater Levels

Regional Groundwater Model Groundwater Levels for the Upper Aquifer Analogue Model

Theory Scaling Factor Equivalent Hydraulic Resistance Tolerance Errors Laboratory Set-up

Investigations on Chloride Levels Sampling Procedure

Sungai Kemasin-Upper Aquifer Interaction

XIV

30 32 33 33 36 38 39 40 41 43

44

44 44 46 5 1 54 55 60 61 62 68 68 69 74 75 76

77 77 79 79 86 87 88 89 90 91 9 1 97

1 00 1 02

VI RESULTS AND DISCUSSION Groundwater Levels 1 04 Intrusion in the Upper Aquifer 1 09

Chloride Contents vs. Distance from the Coast and River 1 1 6 Chloride contents vs. Precipitation 1 16 Chloride contents vs. Landform 1 1 7 Groundwater Flow 1 1 7 Chloride Contributions from Kemasin River 1 1 8 River-Aquifer Relationship 1 23 Groundwater Potential and Sungai Kemasin-Aquifer Flow 1 23

Saline Intrusion in the Lower Aquifer 1 25 Cross-Sectional Saltwater Intrusion Model 128 Initial and Boundary Conditions and Physical Parameters 129 Temporal and Spatial Discretisation of the Cross-Sectional Model 1 3 1 Calibration of the Cross-Sectional Model 132 Transient Saltwater Intrusion Analysis 137 Long-Term Saltwater Intrusion Analysis 140 Sensitivity Analysis 142

SUTRA as a Tool of Analysis 144

VII SUMMARY, CONCLUSIONS AND FUTURE WORK Summary Conclusions

Recommendations for Future Work

BIBLIOGRAPHY APPENDICES

Appendix A: Solving for Concentrations at Specified Nodes using Numerical Approximations in SUTRA model

Appendix B: Plots of Drawdowns and Recovery Pumping Test Data (Kg. Cap)

Appendix C: Data on Stations adjacent to Sungai Kemasin to Establish River-Aquifer Relationship

Appendix D : Recharge Calculations and Associated Data Appendix E: Analogue and PSpice Data for P-Q

Transection Stations Appendix F: Regional Groundwater Model :

Programme, Data and Outputs Two-Zone Programme

Appendix G: Selected Chloride and Groundwater Levels Data For the Upper and Lower Aquifer (including Data on Random Stations)

Appendix H: Plates

BIOGRAPHICAL SKETCH

xv

146 146 148 149

1 5 1

1 62

1 67

1 79

1 88 201

201

23 1

248

256

LIST OF TABLES

Table Page

4. 1 : Results from Previous Study ( 1977) 66

4.2: Results of Pumping Test (Binnie and Partners, 1 980) 66

4.3: Parameters for the Kampong Cap Flow Representation 71

4.4: Parameters for the Kampong Cap Flow System 72

4.5 : Water Quality in Bachok area, Kelantan 75

5 . 1 (a): Voltage Drop with Current Source 2.0 A 96 5 . 1 (b) : The Equivalent Analogue between Discharge and Current 96 5 . 1 (c) : Heights of Stations above sea level 96

6. 1 : Comparison between Measured and Simulated Levels 1 27

Bl: Pumping Test Data 1 7 1

C. 1 : The relationship between the Groundwater Potential with River-Aquifer flow for Sungai Kemasin system (S3) 1 78

C.2: The relationship between the Groundwater Potential with River-Aquifer flow for Sungai Kemasin system (DSM7) 1 78

C.3 : The relationship between the Groundwater Potential with River-Aquifer flow for Sungai Kemasin system (DSN3) 1 79

C.4: The relationship between the Groundwater Potential with River-Aquifer flow for Sungai Kemasin system (DSM4) 1 79

D. 1 : Calculated Runoff for 1 994 19 1

D.2: Summary of Results for July 1 994 1 92

D.3: Daily Rainfall 1 93

D.4: Effective Daily Rainfall 1 94

D.5: Soil Moisture 195

D.6: Water Surplus 1 96

D.7: Water Deficit 197

XVI

D.8: Available Water for Runoff 1 98

D.9: Rainfall and Runoff 1 99

D. lO: Baseflow in m3/s for July 1 994 1 99

E. l : The Analogy between Discharge and Current 202

E.2: Flow of Water, Q (m3/d) for Upper Aquifer (P-Q) 203

E.3: Flow of Water, Q (m3/d) for Lower Aquifer (P-Q) 203

E.4: Flow of Water, Q (m3/d) for Upper and Lower Aquifer (P-Q) With I = 2.0 Ampere - Analog 204

E.5 : Flow of Water, Q (m3/d) for Upper and Lower Aquifer (P-Q) With I = 2.0 Ampere - PSpice 204

E.6: Voltage Drop with Current Source of 2.0 Amperes 205

E.7: Summary of Results using Analog with I = 2.0 A 206

E.8: Height above sea level (I = 2.0 A) - analog 207

E.9: Height above sea level (I:::: 2.0 A) - PSpice 207

E.I0: Summary of Results on Heights (Percentages) 208

G. l : Year 1 994 (Chloride Concentration in mgIL) (Lower Aquifer) 232

G.2: Year 1995 (Chloride Concentration in mgIL) (Lower Aquifer) 233

G.3: Year 1 995 (Groundwater Depth from Ground Level in cm) 234 Lower Aquifer

G.4: Year 1 993 (Chloride Concentrations in mgIL) (Upper Aquifer) 235

G.5 : Year 1 994 (Chloride Concentrations in mgIL) (Upper Aquifer) 236

G.6: Year 1 995 (Chloride Concentrations in mglL) (Upper Aquifer) 237

G.7: Year 1 993 (Chloride Concentrations in mglL) (Upper Aquifer) 238

G.8: Year 1 994 (Chloride Concentrations in mgIL) (Upper Aquifer) 239

G.9: Year 1 995 (Chloride Concentrations in mgIL) (Upper Aquifer) 240

xvii

G. lO: Year 1 995 (Chloride Concentrations in mgIL) (Upper Aquifer) 241

G.l l : Data of Rainfall Amount, Groundwater Level and Chloride Concentration 242 for Stations T18, TI9 and DSNl

xviii

LIST OF FIGURES

Figure Page

2. 1 : Interface between Freshwater and Saltwater (Ghyben-Herzberg Theory) 8

3 . 1 : Groundwater Flow Near the Coast (Sharp Interface Theory) 1 9

3.2: Two-dimensional Finite Element Mesh and Quadrilateral Element 40

4. 1 : Location of the Study Area 45

4.2: Major Soil Types within the Study Area 47

4.3: Geology of Ke1antan 49

4.4 (a) : Average Rainfall over 20-years (Bachok: Station Number 6024704 50

4.4 (b): Rainfall Pattern during the Study period 50

4.5 : Zonation of Hydrochemical Facies (water type) in Kelantan Basin 53

4.5 (a) : The Three Aquifer Zones, Bachok District 56 4.5 (b): Location ofthe Cross-Section (Plan) 57 4.5 (b) : Hydrogeological Cross-Section (Bachok, Kelantan) 58 4.5 (d): Locations of Test and Observation Wells 59

4.6: The Transmissivities of the Kelantan Lower Aquifer 67

4.7 (a) : Flow Representation of Kg. Cap Test Well 70 4.7 (b): Two-Zone Model Approach 70

4.8: Predicted and Field Drawdowns for Pumping Duration of2.7 days 73

5 . 1 : Field Investigation Set-up for Upper and Lower Aquifers 78

5 .2 : Water Table Condition of Kelantan Aquifer on 1 st. December 1 994 85

5.3 (a): Aquifer Profile 92

xix

5.3 (b): Location of Stations along the transect P-Q from Pantai Irama, Bachok 93

5 .4 (a): Node and Resistor Division 94 5 .4 (b): Analogue Model 95

5.5 : Schematic Diagram ofPizeometer 98

5 .6 : Location of Transects and Piezometers within the 99 Northern part of the Study Area

5.7 (a): Typical Relationship between Flow from Aquifer to the River and Groundwater Potential 103

5 .7 (b) : The Cross-Section ofthe River-Aquifer interactions 1 03

6. 1 : Location of the Piezometer and 'Control' Transection 105

6.2 : Water Levels below GL (DSS3-DSS1 ) (Nov.'93-June '95) and (N3-N1) (Nov. '92-June'95 1 08

6.3 (a): Chloride Levels for DSS 1 -DSS5 (Nov. '93-June '95 (,Control') Chloride 1 1 1 6.3 (b): Levels of Electrical Conductivities (E.C.) in (�S/cm for 1 1 1

Transect (DSSI-DSS5) ('Control')

6.4 : The chloride Levels for the Northern Transect (N 1 -NS) and without (N3&N4) (Nov.'92-June'95) 1 1 3

6.5 : Chloride Levels for Southern Transect (with and without S3 and S4) 1 14

6.6 (a): Variation of Chloride Content in Groundwater in the Northern Transect in Relation to Rainfall and Landscape 1 1 9

6.6 (b): Variation of Chloride Content in Groundwater in the Middle Transect in Relation to Rainfall and Landscape 1 20

6.6 (c ) : Variation of Chloride Content in the Groundwater in the Southern Transect in Relation to Rainfall and Landscape 121

6 .7 : Chloride Levels in December '93 and '94 1 22

6.8 (a), (b), (c) The Relationship between Groundwater Potential with and (d) River- Aquifer Flow for Sungai Kemasin System 1 24

xx

6.9 : Water Table Condition of Kelantan Aquifer on 1 st. December 1 994 showing Measured and Computed Water Levels for Bachok area 1 26

6. 10 : Comparison of Observed and Computed Heads along Section P-Q 1 28

6. 1 1 : Piezometers, Production Wells and Boundary Conditions for the Cross-Section Model 1 30

6. 12 : Cross-sectional Finite Element Mesh for the Bachok plain P-Q Transection 1 30

6. 1 3 : Chloride Concentration (Measured) vs. Distance in 1 994 for P-Q Transection 133

6 . 14 : Chloride Concentration (Measured) vs. Distance in 1 995 for P-Q Transection 133

6. 1 5 : Depth vs. Chloride Concentration (Measured) in 1 994 for P-Q Transection 1 34

6. 1 6 : Depth vs. Chloride Concentration (Measured) in 1 995 for P-Q Transection 134

6. 1 7 : Comparison of Calibrated Concentration Isochlors (seawater = 1 .0), Ghyben-Herzberg and Measured Levels 1 36

6. 1 8 : The initial and Final Salt Concentration Distribution (seawater = 1 .0) for Complete Period of Dry and Recharge 139

6. 1 9 : Comparison of Salt Concentration Distribution (seawater = 1 .0) for t = 0 year and t = 25 year 141

6.20 : Sensitivity Analysis for the Cross-Section Model of P-Q Transection 143

B. l : Drawdown and Recovery Plots for BH4 168

B. l : Drawdown and Recovery Plots for BH5 1 69

xxi

B. l : Drawdown and Recovery Plots for ENEX Borehole 1 70

C. 1 : River-Aquifer Interaction for Sungai Kemasin, Station S3 1 80

C.2: River-Aquifer Interaction for Sungai Kemasin, Station S4 1 8 1

C.3: River-Aquifer Interaction for Sungai Kemasin, Station DSM6 1 82

C.4: River-Aquifer Interaction for Sungai Kemasin, Station DSM7 1 83

C.5 : River-Aquifer Interaction for Sungai Kemasin, Station DSN2 1 84

C.6: River-Aquifer Interaction for Sungai Kemasin, Station DSN3 1 85

C.7: River-Aquifer Interaction for Sungai Kemasin, Station DSM3 1 86

C.8: River-Aquifer Interaction for Sungai Kemasin, Station DSM4 1 87

D: Unit Hydrograph for July 1 994 200

E. 1 : Comparison of Voltage drop between Analog and PSpice 209

E.2: Comparison ofField, Analog and PSpice Head Values 210

G. 1 : Relationship between Rainfall Amount, Groundwater Level and the effect on Chloride Concentration at T 18 243

G.2: Relationship between Rainfall Amount, Groundwater Level and the effect on Chloride Concentration at T 19 244

G.3 : Relationship between Rainfall Amount, Groundwater Level and the effect on Chloride Concentration at DSNI 245

G.4: Relationship between Rainfall Amount, Groundwater Level Chloride Concentration at T1 8, T19 and DSNI 246

G.5 : The Comparison between Chloride Concentration at each Station (TI 8, T19 and DSNl) 247

xxii

LIST OF PLATES

Plate Page

5 .4 (b) Analogue Model 95

H I A View o f Sungai Kemasin ('Salty River') 249

H2 Water Table Measurement Set 249

H3 Measuring Depth to Water Table (Location T 1 8) 250

H4 Pumping out the Sample (Location DDM4) 250

H5 Tobacco Cultivation in the Study Area 25 1

H6 'Floating Bridge' across Kemasin River 25 1 (Location DDN3)

H7 Pumping the Sample at Location DDN5 252

H8 Measuring Water Table at Location DDM3 252

H9 Kg. Cap Water Treatment Plant 253

HIO Production well at Kg. Cap Treatment Plant (formerly Test Well l) 253

Hll Jelawat Treatment Plant (Transect DDS 1 - DDS5) 254

Hl2 Production Well at J elawat 254

H13 Level Gauge in Kemasin river 255

H14 Tidal Gate 255

xxiii

b

c

c

c·

cumecs

D

D

g

h

I

K

k

MARDI

p

ppm

q

R

LIST OF SYMBOLS AND ABBREVIATIONS

thickness occupied by the indicated fluid (L)

concentration (MC3)

the fluid solute mass fraction

the solute mass fraction of fluid sources

cubic metres per second

hydrodynamic dispersion coefficient (L2Tl)

the dispersion tensor

the apparent molecular diffusivity of solutes in solution in a porous medium including tortuosity effects

gravitational acceleration (LT2)

fresh-water head (L)

salt-water head (L)

head in overlying aquifer (L)

identity tensor

hydraulic conductivity (a tensor quantity)

intrinsic permeability (L2)

Malaysian Agricultural Research and Development Institute

pressure (ML-1 T2)

parts per million

fluid mass source

Darcy velocity (LTl)

recharge (L)

specific storage in fresh-water zone

xxiv