EFFECTIVENESS OF SEDIMENT BASIN AND SILT TRAPS AT

OIL PALM PLANTATIONS

NUR SYAHIZA BINTI ZAINUDDIN

A project report submitted in partial fulfillment of the

requirements for the award of the degree of Master of

Engineering (Civil-Environmental Management)

Faculty of Civil Engineering

Universiti Teknologi Malaysia

JUNE 2007

iii

To

Beloved parents;

Mr. Zainuddin Said & Mrs. Jamilah Yusoff

&

Beloved sisters & brothers;

Halawati, Aini, Nazmi & Syafiq

For all of their patience and understanding

In the past, present, and future

iv

ACKNOWLEDGEMENT

“In the name of God, the most Gracious, the most Compassionate”

First & foremost, it is pleasure to record my love and gratitude to my parents,

Mr. Zainuddin Said and Mrs. Jamilah Yusoff, and my family for their love, patience,

support, encouragement and sustaining my spirits.

I wish to extent my sincerest thanks to PM Dr Mohd Ismid bin Mohd Said,

from whom I received the greatest supervisor throughout my work. His criticisms

and suggestions have been extremely valuable in the development of this study.

Without his patience and unfailing support and guidance, this report would not have

been same as presented here.

I also would like to express my special thanks to Mr. Zaidi Zin from IZ

Environmind Sdn. Bhd. and his staff, for supplying invaluable data and maps which

are crucial for this study. Thanks again to them for the kindness and helping hand

whenever I encountered difficulties while accomplishing the project.

Finally, I would like to extend my appreciation and thanks to all my beloved

friends and for those who had given me assistance directly or indirectly for their

understanding during ups and downs as I pursued my Master degree.

May all the good deeds that were done will be blessed by Allah. Wassalam…

v

ABSTRACT

In recent year, there has been an increasing comment over deterioration of

water quality in many river systems in Malaysia. Therefore, this study analyse

the effectiveness of implementing various types of sediment basin and silt trap in

oil palm plantation located at Gua Musang. The district of Gua Musang is a

major producer of oil palm plantation in Kelantan with the total area of 55 191

hectares. The aim of this study is to identify whether the water from this oil palm

plantation be a part of contributor of the problem happened in Sg. Kelantan

which is nowadays become shallow and polluted because of sedimentation

problem. In this study there were three sediment basins has been analysed. A

field measurement on suspended solid, turbidity and sediment loading was

carried out before and after sediment basin. The range of Suspended Solid is

between 5 mg/L to 50 mg/L before the sediment basins and 1 mg/L to 14 mg/L

after sediment basins. Turbidity gives a result between 4.7 NTU to 79.0 NTU

before the sediment basins and 5.8 NTU to 42.0 NTU after the sediment basins.

From these data, total sediment loading per hectares was calculated and

compared to the amount calculate by using USLE and MSLE formula. Beside

that, the examination upon efficiency of sediment elimination was done and each

sediment basin gave a result of 80%, 37.5% and 72%. However from

questionnaire analysis on environmental awareness, the result shows that most

developers and their workers awareness are still in moderate and low level.

vi

ABSTRAK

Dewasa ini isu berkenaan kemerosotan kualiti air sungai-sungai yang terdapat

di Malaysia semakin meningkat. Oleh yang demikian, kajian ini bertujuan untuk

mengenalpasti keberkesanan kepelbagaian perangkap keladak yang dilaksanakan di

ladang kelapa sawit di Gua Musang sebagai salah satu usaha pengawalan

kemerosotan kualiti air. Daerah Gua Musang merupakan kawasan perladangan

kelapa sawit utama di negeri Kelantan dengan keluasan 55 191 hektar. Matlamat

kajian ini adalah untuk mengenalpasti samada aliran yang mengalir dari ladang

kelapa sawit ini turut menyumbang kepada masalah yang berlaku di Sungai Kelantan

di mana pada hari ini didapati semakin cetek & dan tercemar akibat daripada masalah

pemendapan. Tiga perangkap keladak dianalisis. Pengukuran terhadap beberapa

parameter kualiti air seperti pepejal terampai, kekeruhan dan beban sediment dibuat

sebelum dan selepas perangkap keladak. Pepejal terampai memberi keputusan antara

5 mg/L hingga 50 mg/L sebelum perangkap keladak manakala 1 mg/L hingga 14

mg/L untuk selepas perangkap keladak. Kekeruhan memberi nilai antara 4.7 NTU

hingga 7.90 NTU dan 5.8 NTU hingga 42 NTU masing-masing untuk sebelum dan

selepas perangkap keladak. Daripada data tersebut, beban sedimen dikira dan

perbandingan dibuat dengan menggunakan kaedah USLE dan MSLE. Selain itu,

pemeriksaan terhadap keberkesanan penyingkiran keladak juga dianalisis dan ketiga-

tiga perangkap yang dikaji masing-masing memberi peratus 80%, 37.5% dan 72%.

Walaubagaimanapun, daripada keputusan analisa soal selidik, didapati tahap

kesedaran terhadap kepentingan alam sekitar dikalangan pengusaha dan pekerjanya

masih di peringkat sederhana dan perlu dipertingkatkan.

vii

TABLE OF CONTENT

CHAPTER PAGE

TITLE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENT vii

LIST OF TABLE xi

LIST OF FIGURE xiii

LIST OF PHOTO xv

LIST OF SYMBOL xvi

LIST OF ABBREVIATION xvii

LIST OF APPENDICES xviii

I INTRODUCTION

1.1 Preamble 1

1.2 Problem Statement 2

1.3 Aim of Study 6

1.4 Objective 6

1.5 Scope of Study 6

viii

II LITERATURE REVIEW

2.1 Introduction 8

2.2 Application of Sediment Basin 8

2.2.1 Sediment Basin Efficiency 10

2.3 Application of Silt trap 11

2.4 Suspended Solids 11

2.4.1 Factors affecting Settlement of TSS 12

2.5 Fundamental of Sedimentation 13

2.5.1 Newton’s and Stokes’ Sedimentation 14

Laws

2.5.2 Hazen’s Surface Load Theory 14

2.6 Sediment Loading 15

2.7 Pollutant Load Modeling System 15

2.7.1 Universal Soil Loss Equation (USLE) 16

2.7.2 Modified Soil Loss Equation (MSLE) 16

2.7.3 Event Mean Concentration (EMC) 17

2.7.4 Pollutant Export Rate Method 18

2.8 Soil Erosion 18

2.8.1 Theory of Erosion by Water 19

2.8.2 Primary Factors Influencing Soil Erosion 19

By Water

2.8.3 Soil and Water Erosion Pollution Control 21

2.9 Oil Palm Plantation 21

2.9.1 Typical Project Activities 22

2.9.1.1 Pre-Development 22

2.9.1.2 Nursery Development 23

2.9.1.3 Site Preparation 23

2.9.1.4 Field Establishment 24

2.9.1.5 Maintenance & Harvesting 24

2.10 Environmental Preservation 25

2.11 Effect of Rainfall Distribution and Climates 25

Change on Oil Palm Plantation

2.12 Summary 27

ix

III METHODOLOGY

3.1 Data Requirement 28

3.2 Primary Data 28

3.3 Secondary Data 29

3.3.1 Water Quality Parameter 29

3.3.2 Rainfall Distribution Data 31

3.4 Method of Analysis 31

3.4.1 Trend analysis 31

3.4.2 Comparison with Standard Requirement 31

3.4.3 Questionnaire Study 32

3.4.3.1 Survey Question 32

3.4.3.2 Data Interpretation 33

IV STUDY AREA

4.1 Introduction 34

4.2 Project Site Background 37

4.3 Existing Physical Environment 39

4.3.1 Surrounding Land Use 39

4.3.2 Topography 39

4.4 Meteorology Characteristic 41

4.4.1 Average Rainfall 41

4.5 Existing Drainage Pattern 43

4.6 Existing Sediment Basin & Silt Trap 43

V RESULT AND DISCUSSION

5.1 Introduction 49

5.2 Sediment Basin and Silt Trap Analysis 50

5.2.1 Total Suspended Solids (TSS) 50

5.2.2 Turbidity 51

5.2.3 Other Water Quality Parameters 51

5.2.4 Sediment Elimination Efficiency 53

5.2.5 Sediment Basin Design Efficiency 54

x

5.2.5.1 Sizing of Sediment Basin 54

5.2.5.2 Settling Zone 56

5.3 Erosion Risk Analysis 57

5.3.1 Total Sediment Loading Estimation 58

5.3.1.1 Flowrate 58

5.3.1.2 Sediment Loading Estimation 58

5.3.2 Assessment of Factors Influencing Soil 60

Erosion And Sedimentation

5.3.2.1 Rainfall Factor (R) 60

5.3.2.2 Soil Erodibility (K) 60

5.3.2.3 Length-Slope Factor (LS) 61

5.3.2.4 Cover Management Factor (C) 61

5.3.2.5 Conservation Practice Factor (P) 62

5.3.2.6 Management Factor (VM) 62

5.3.3 Assessment of Soil Erosion Rates using 62

USLE Methods

5.3.4 Assessment of Soil Erosion Rates using 63

MSLE Methods

5.4 Water Quality Analysis 65

5.4.1 River Classification based on WQI 65

5.4.2 Trend Analysis for Suspended Solids 68

Parameter

5.5 Correlation Between Planting Stage and Rainfall 70

Distribution Analysis

5.6 Questionnaire Analysis 72

5.7 Discussion 76

VI CONCLUSION AND RECOMMENDATIONS

6.1 Conclusion 79

6.2 Recommendations 80

REFERRENCES 82

APPENDICES 88

xi

LIST OF TABLE

NO

TITLE

PAGE

1.1 Flood impact in Kelantan 3

1.2 Statistics of oil palm land area at Malaysia 4

2.1 Factors contribute to erosion phenomenon 19

3.1 Date on purpose sampling process for plantation 1 30

3.2 Date on purpose sampling process for plantation 2 30

3.3 Topic in the questionnaire 32

3.4 Questionnaire scale 33

4.1 Cultivated area by district in Kelantan 36

4.2 Characteristic for each project site 41

4.3 Characteristic for each sediment basin located in both study

areas

44

5.1 Suspended solids result 50

5.2 Turbidity result 51

5.3 Water quality result for each of sediment basins found in the

study area

52

5.4 Dry sediment basin sizing guidelines 55

5.5 Sediment basin size required based on MASMA guideline 56

5.6 Characteristic for each sediment basin 56

5.7 Sediment loading estimation per hectare per year 59

5.8 Exponent m based on slope percent 61

5.9 Erosion analysis using USLE method 63

5.10 Erosion analysis using MSLE method 63

xii

5.11 Classification for soil erosion risk 64

5.12 Water quality index (WQI) results for Sg. Wah and Sg.

Sungkai

65

5.13 Water Quality Index (WQI) (DOE, 1986) 66

5.14 Water quality monitoring results for Sg. Wah and Sg.

Sungkai

67

xiii

LIST OF FIGURE

NO

TITLE

PAGE

1.1 Satellite view of Kelantan River 3

2.1 Percent reduction in TSS vs. the TSS concentrations in the

inflow

13

2.2 Example of flow disturbances in a basin 14

2.3 Flow diagram of typical oil palm plantation development

activities

26

4.1 Location of Gua Musang 35

4.2 Total percentage for each types of plantation area at Gua

Musang

36

4.3 The location plan for both project sites 38

4.4 Topography map of plantation 1 project site 40

4.5 Topography map of plantation 2 project site 40

4.6 Trend of rainfall distribution at Cameron Highlands rainfall

station

42

4.7 Sediment basin cross section 44

4.8 Location of SB1 and SB2 in plantation two site area 47

4.9 Location of SB3 in plantation 2 site area 48

5.1 Suspended solids trend at Sg. Wah 68

5.2 Suspended solids trend at Sg. Sungkai in plantation 1 69

5.3 Suspended solids trend at Sg. Sungkai in plantation 2 70

5.4 Correlation between planting stage and rainfall amount 71

5.5 Result from questionnaire analysis for part A 73

xiv

5.6 Result from questionnaire analysis for part B 73

5.7 Result from questionnaire analysis for part C 74

5.8 Result from questionnaire analysis for part D 74

5.9 Result from questionnaire analysis for part E 75

5.10 Result from questionnaire analysis for part F 75

xv

LIST OF PHOTO

NO

TITLE

PAGE

2.1 Sediment basin can be temporary or permanent 10

2.2 Sediment basin are used to trap sediments on larger

construction sites

10

4.1 Well establish sediment basin found in plantation 1 labeled

as SB1

45

4.2 Condition of SB2 sediment basin which is still in

construction phase

46

4.3 Single sediment basin (SB3) found located in plantation 2

site area

46

xvi

LIST OF SYMBOL

A - Catchment area

a - An empirical coefficient

C - Erosion control practice factor

Ĉ - EMC of pollutant

E - Mean annual soil loss

e - An empirical exponent

ha - hectare

K - Factor of the soil erodibility

km - Kilometer

L - Annual load of Pollutant

m - Meter

mg - Milligram

P - Factor expressing the effects of conservation

R - Rainfall erosivity factor

S - Slope steepness factor

s - second

V - Settling zone

VM - Vegetation management factor

VR - Annual runoff depth

W - Average width

Y - Zone depth

xvii

LIST OF ABBREVIATION

AN - Ammoniacal Nitrogen

BOD - Biochemical Oxygen Demand

COD - Chemical Oxygen Demand

DO - Dissolved Oxygen

DOE - Department of Environment

EIA - Environmental Impact Assessment

EME - Environmental Monitoring Exercise

EMP - Environmental Monitoring Plan

INWQSM - Interim national Water Quality Standard for

Malaysia

IZE I. Z. Environmind

JUPEM - Jabatan Ukur dan Pemetaan

KHSB - Kapasiti Harapan Sdn. Bhd.

MPOB - Malaysian Palm Oil Board

MSLE - Modified Soil Loss Equation

POMs Palm Oil Mills

PVSB - Peransang Venture Sdn. Bhd.

SS - Suspended Solid

TSS - Total suspended solids

USLE - Universal Soil Loss Equation

WQI - Water Quality Index

xviii

LIST OF APPENDICES

NO

TITLE

PAGE

1.1 Articles in The Star Newspaper (28/03/07) Report on

Kelantan’s Lojing Highlands in Danger of Being Logged

Bare

88

1.2 Article in The Star Newspaper (28/03/07) Report on Forest

Reserve Under Treat Issue

89

3.1 Records of Monthly Rainfall Amount 90

3.2 Records of Number Of Raindays 91

3.3 DOE Water Quality Index Classes 92

3.4 Interim National Water Quality Standards For Malaysia 93

3.5 Questionnaire Form 95

5.1 Sediment Basin Types 97

CHAPTER I

INTRODUCTION

1.1 Preamble

When land is disturbed either for construction, agriculture, road building,

mining, logging, or other activities, the soil erosion rate increase from 2 to 40 000

times (Goldman et. al., 1986). The effect of this phenomenon is millions of tons of

the soil end up in our rivers, lakes, and reservoirs. Each year, billions of dollars have

to spend by land developers or property owner in order to cleaning up sediment and

repairing eroded stream banks, gullied hillsides, washed-out roads, mud chocked

drains and other erosion damage.

Most erosion will cause sediment problem and this can be greatly reduced by

proper planning and maintenance. Some of the methods are by using sediment basin

and silt trap. We should bear in mind that these structures does not stop erosion.

They only trap eroded soil before it can reach water body or adjacent property.

Generally, a sediment basin is designed to remove and retains portions of the

sediment being carried by runoff. In essence, they work by slowing the velocity of

runoff and letting suspended soil particles settle by gravity. During periods of heavy

rainfall sediment basin or silt trap constructed in oil palm plantation site must be

fully function to soakaways retain water and soil run-off. Therefore, leaf matter left

2

on slope from trimming the palm trees to harvest the fruit should be used to reinforce

terraces or to otherwise create erosion barriers on contours. The other way is by

construct silt pits along roads and in fields to trap eroded soil carried in runoff.

From management aspect, before any land is to be developed for oil palm

cultivation, an Environment Impact Assessment (EIA) must be undertaken to ensure

that there are no adverse effects on the environment arising from the cultivation of

the crop. A detailed Environmental Monitoring Plan (EMP) with institutional

reporting requirements, and parameters for monitoring of water quality,

agrochemical usage, impact on aquatic life, changes in forest and wildlife and other

impacts as based on public consultations must be included in the EIA study.

Environmental monitoring, auditing and surveillance must be conducted to

ensure that all the works done are comply with the regulations and conditions lay

down by the Department of Environment (DOE) prior to the commencement of a

project.

1.2 Problem Statement

Kelantan River or namely as Sungai Kelantan in Malay language is the major

river in Kelantan, Malaysia. It drains a catchment area of about 12 000 km² in north-

east Malaysia and flows northwards into the South China Sea. The rainfall over the

area varies between 0 mm in the dry season (March-May) to 1750 mm in the

monsoon season (November-January). The average runoff from the area is about 500

m³/s. Figure 1.1 shows the satellite view of Kelantan River.

The Kelantan River regularly overspills its banks either during the months of

November to February because of the northeast monsoon season or others reason.

Some of the worst floods in recent years are listed in table 1.1 (Hazalizah, 2005).

3

Figure 1.1: Satellite view of Kelantan River

(source: http://www.worldwindcentral.com)

Table 1.1: Flood impact in Kelantan

Year Evacuees Deaths Damage (US$1000)

2004 10 476 12 3 767

2003 2 228 2 1 461

2001 5 800 0 2 227

1993 13 587 0 3 98

1988 41 059 0 *

1986 7 963 0 1 603

1983 33 815 0 *

* Data not available

4

This flood phenomenon occurs because of many reasons. Latest issues

contribute to this problem was report in The Star newspaper on 28 March 2007

where the last frontier in Lojing Highlands, Kota Bharu state with lush forest reserve

is now in danger of being log bare and will give big impact on the state’s ecology.

The articles of this report are shown in Appendix 1.1 and 1.2. The existing impact

has been studied and the result found that nowadays Kelantan River is become

shallow and cannot provide irrigation resources to paddy farmers nearby. If this

problem is not protected, it will affect the state’s future natural resources which may

be compromised by excessive logging. The purpose of logging activities carried out

at this area is for development of oil palm plantation.

Oil palm (Elaeis guineensis) was first introduced into Malaysia as an

ornamental plant in 1870 (Williams et. al., 1970). The cultivation of oil palm has

grown every year since 1960 when the Malaysian government embarked on a

massive agricultural diversification programme. It has now become the cornerstone

of the country's agricultural sector, with a planted area of 4 165 215 hectares in 2006

(MPOB, 2006). Table 1.2 shows the statistics of oil palm land area at Malaysia for a

few latest years. From that total area, Kelantan was covered about 80 152 hectares

and Gua Musang is the main oil palm manufacturer for this state. Based on Country

& Land Office of Gua Musang, the total area of oil palm cultivation in 2001 situated

in Gua Musang is 51 170.5 hectares.

Table 1.2: Statistics of oil palm land area at Malaysia

Land Area (ha) under Oil Palm Cultivation (1975-2006)

1980 1985 1990 1995 2000 2003 2004 2005 2006

1 023 306 1 482 399 2 029 464 2 540 087 3 376 644 3 802 040 3 880 000 4 051 374 4 165 215

(Source: MPOB Malaysia, 2006)

Oil palm cultivation can cause erosion and sedimentation during its operation.

This sediment will wash away into the lakes, rivers and waterways. Although this

sediment is only a fraction of the total sediment load, it is a major source of pollution

5

of many lakes, streams and river. Eroded soil contains nitrogen, phosphorus, and

other nutrients (Goldman et. al., 1986). When carried into water bodies, these

nutrients trigger algal bloom that reduce water clarity, deplete oxygen, lead to fish

kills and create odors. Turbidity from sediment also reduces in-stream

photosynthesis, which leads to reduce food supply and habitat.

To prevent eroded soil or sediment from polluted the nearest river or stream,

one of the methods that can be implementing is by using sediment basin or silt trap.

Nowadays, there is very little performance data on sediment or silt structures at one

site. All too often these structures have been constructed with major flaws which

prevent good performance. In other cases, these sediment basin and silt trap have

been properly constructed but not monitored or maintained.

The fact is, those structures required maintenance and cleaning at regular

intervals. If too much sediment is allowed to accumulate in them, they will cease to

function. Little or no settling will occur, and trapped sediment will be resuspended

and washed away. Finally, sediment basin can pose a safety hazard to human when

water is impounded in them.

Awareness on above phenomenon was the main reason why this study was

conducted. Two main areas were chosen around Gua Musang. First project site was

initiated by Kapasiti Harapan Sdn. Bhd. (KHSB) which is located at PT 4957 &

4958, Mukim Ulu Nenggiri, Daerah Bertam, Gua Musang, Kelantan Darul Naim.

This oil palm site is situated adjacent to the north, south and east of Hutan Rizab

Sungai Betis and west of Hutan Rizab Sungai Papan. Total area for this project site is

3 000.00 acres (1, 214.06 hectares).

The second project site was initiated by Peransang Venture Sdn. Bhd.

(PVSB). PVSB have been given responsibility to develop approximately 2,000.00

acres (809.39 hectares) land located at PT 5011, Mukim Ulu Nenggiri, Daerah

Bertam, Gua Musang, Kelantan into an oil palm plantation project. This project site

is located adjacent to the north, south, west and east of Hutan Rizab Sungai Betis.

Both project sites are situated near the main river and small rivulets which found

scattered within the project area. Therefore, it is important to study the effectiveness

6

of sediment basin and silt trap constructed at both side in order to check the

efficiency.

1.3 Aim of Study

The aim of this study primarily at deriving the level of effectiveness and

awareness on sediment basin and silt trap implemented in oil palm plantation at Gua

Musang.

1.4 Objective

The objective of this study was three-fold, namely:

i. To determine the efficiency of sediment basin and silt trap implemented in oil

palm plantation.

ii. To analyze the trend of water quality at the project sites.

iii. To identify the level of environmental awareness among developers or

planters involve in oil palm plantation project.

1.5 Scope of Study

The scope of the study covers all types of sediment basin and silt trap located

at two oil palm plantation given below:

i. Oil palm plantation at PT 4957 & 4958, Mukim Ulu Nenggiri, Daerah

Bertam, Gua Musang, Kelantan Darul Naim which initiated by Kapasiti

Harapan Sdn. Bhd. (KHSB), and

7

ii. Oil palm plantation at PT 5011, Mukim Ulu Nenggiri, Daerah Bertam, Gua

Musang, Kelantan Darul Naim which initiated by Peransang Venture Sdn.

Bhd. (PVSB).

This study will concentrate on deriving the effectiveness of sediment basin

and silt trap implemented in oil palm plantation in Gua Musang. The effectiveness

will be determined based on considering a few factors. Suspended solid and turbidity

are the main parameter studied for both sediment basin and silt trap. Assessment on

water quality of water bodies on selected parameters namely pH, Dissolved Oxygen

(DO), temperature, Biochemical Oxygen Demand (BOD), Chemical Oxygen

Demand (COD), Suspended Solid (SS), Ammoniacal Nitrogen (AN), E-Coli and Oil

& Grease are also conducted to analyze water quality at the site.

Beside that, erosion risk analysis was also done by comparing with Universal

Soil Loss Equation (USLE) method and Modified Soil Loss Equation (MSLE)

method. This study also conducted interview session with project proponent and

workers in order to analyze their level of environmental awareness on implementing

oil palm plantation project.