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UNIVERSITI PUTRA MALAYSIA

APPLICATION OF SWAT HYDROLOGICAL MODEL WITH GIS INTERFACE TO UPPER BERNAM RIVER BASIN

LAI SAI HIN

FK 2001 26


By

LAI SAI HIN

Thesis Submitted in Fulfilment of the Requirement for the Degree of Master of Science in the Faculty of Engineering

Universiti Putra Malaysia

March 2001

Abstract of thesis presented to the Senate ofUniversiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science.


By

LAI SAI HIN

March 2001

Chairman : Associate Professor Ir. Dr. Mohd. Amin Mobd. 800m

Faculty : Engineering

Rising concern over the degradation of the environment due to rapid land development

in recent years has created a need for watershed modeling. The Upper Bemam River

Basin in South Perak and North Selangor, Malaysia was chosen for this study. This

study was carried to evaluate the effectiveness of a GIS interface physically based

hydrologic model (SWAT) in predicting surface runoff and sediment load from a basin

scale watershed. The effects of land use changes on runoff and sediment loading rate

were also studied.

The data required for this study is the topographical, hydrometeorological, soil, and the

land use data. All of them are integrat�d in a GIS in tabular, vector and grid formats.

The land use data in this study were derived from Landsat TM images. These images

were enhanced and classified using a combination of different classification strategies.

ii

The classified land use maps compares reasonably well with the map showing broad

vegetation types of the river basin with an accuracy of 95%.

Due to recent rapid land use changes, the model was run in a short term basis. The

results from model application and statistical analysis show that SW AT generally does a

good job in predicting both runoff flow and sediment load with a an average gap of 22%

and 34% respectively between observed and predicted results. The exception is for

those days with very heavy rainfall (> 35 mmJday), SWAT seriously overestimated

runoff.

Results from historical data, trend analysis, and calculated runoff rate and sediment

loading rate due to open area have also shown the close relationship between surface

runoff, sediment load and open area downstream of the upper river basin. It is found

that the average increment of sediment loading rate for the study area ranges from 1 .47

to 2 .06 tonnes per millimeter of rainfall for each kilometer-square increase of open

areas.

iii

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk Ijazah Master Sains


Oleh

LAI SAIBIN

Mac 2001

Pengerusi : Profesor Madya Ir. Dr. Mohd. Amin Mohd. Soom

Fakulti : Kejuruteraan

Kesedaran tentang ancaman pembangunan tanah yang pesat terhadap alam sekitar di

Malaysia beberapa tabun ini mencetuskan keperluan pemodelan lembangan sungai. Hulu

Lembah Bemam yang berada di Selatan Perak dan Utara Selangor, Malaysia telah

dipilih untuk kajian ini. Kajian ini telah dijalankan untuk menguji keberkesanan satu

model hidrologi yang berteraskan GIS untuk menganggar aliran permukaaIl dan endapan

dari sebuah lembangan tadahan air. Kesan guna tanah terhadap aliran permukaan dan

endapan juga telah dikaji.

Data yang diperlukan untuk kajian ini ialah data yang berkenaan dengan topografi,

hidrocuaca, tanah, dan data guna tanah, dimana semua data tersebut telah diintegrasikan

dalam satu pangkalan data GIS dalam bentuk jadual, vektor, dan grid. Data guna tanah

yang digunakan dalam projek ini adalah diperolehi daripada imej Landsat TM. Imej

tersebut telah diperbaiki dan dikelaskan dengan menggunakan satu kombinasi strategik

iv

klassifikasi yang berlainan. Hasil peta guna tanah yang dikelaskan adalah baik setelah

dibandingkan dengan peta yang menunjukkan jenis tumbuhan umum di lembangan

tersebut dengan satu ketepatan 95%.

Disebabkan perubahan guna tanah yang kerap, permodelan telah dijalankan untuk satu

tempoh yang singkat. Keputusan daripada pengunaan model dan analisis statistik

menunjukkan bahawa SWAT secara umumnya adalah baik untuk menggangar kedua

duanya aliran permukaan dan endapan dengan satu jurang 22% dan 34% masing-masing

di antara data data yang dipunggut dan data data yang dianggar, kecuali untuk hari-hari

yang mempunyai hujan lebat (> 35 mmlday), SWAT telah lebih anggar aliran

permukaan dengan serius.

Hasil dari data yang lepas, tren analisis, kadar aliran permukaan dan kadar endapan

terhadap kawasan terbuka yang dOOra juga telah menunjukkan perhubungan yang rapat

di antara aliran permukaan, endapan, dan kawasan terbuka di bahagian hilir lembangan

sungai tersebut. Adalah ditemui bahawa untuk setiap kilometer persegi pertambahan

dalam kawasan terbuka, kadar endapan purata telah bertambah sebanyak 1 .47 hingga

2.06 ton per milimeter air hujan.

v

ACKNOWLEDGEMENTS

With a deep sense of gratitude the author would like to acknowledge his project

supervisory team Associate Professor Ir. Dr. Mohd. Amin Mohd. Soom, Assoc. Prof.

Kwok Chee Yan and Dr. Abdul Rashid Mohamed Shariff for their invaluable guidance,

constructive suggestions and encouragement throughout the duration of this project.

Sincere thanks are extended to Dr. Lim Jit Sai and Mr. Rao of the Department of

Agriculture Malaysia for providing the unpublished detailed soil data and land use maps

of study area. Thanks are also extended to the staff of Hydrology Branch of Drainage

and Irrigation Department, the staff of Malaysian Meteorological Services, and the staff

of Malaysian Centre for Remote Sensing (MACRES) for providing related

hydrometeorological and satellite data used in this study. Special thanks are for Prof.

Nancy Sammons (USDA, ARS-Temple) and Prof. Mauro Diluzio (Texas A&M

University, TAES-Temple) for their valuable reading materials and technical

assistantship (model updating and error checking) in watershed modeling.

Lastly, the author would like to express his sincere appreciation to his family for

their undying love, patience, encouragement and supports during the course of study.

Vi

I certify that an Examination Committee met on 24th March 2001 to conduct the final examination of LAI SAl HIN on his Master of Science thesis entitled "Application of SWAT hydrological model with GIS interface to Upper Bemam Basin" in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulation 1981. The committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committees are as follows:

LEE TEANG SHUI, PhD. Department of Biological and Agricultural Engineering, Faculty of Engineering, Universiti Putra Malaysia (Chairman)

MOH». AMIN MOHD. SOOM, PhD. Department of Biological and Agricultural Engineering, Faculty of Engineering Universiti Putra Malaysia (Member)

KWOK CHEE YAN Department of Biological and Agricultural Engineering, Faculty of Engineering Universiti Putra Malaysia (Member)

ABDUL RASHID MOHAl\fED SHARIFF, Ph.D. Department of Biological and Agricultural Engineering, Faculty of Engineering, Universiti Putra Malaysia (Member)

---

HAZALI MOHA YIDIN, Ph.D. Professor Deputy Dean of Graduate School, Universiti Putra Malaysia.

Date: 1 0 APR 2001

vii

This thesis submitted to the Senate of Universiti Putra Malaysia has been accepted as fulfilment of the requirements for the degree of Master of Science.

MOHD. GHAZALI MORA YIDIN, Ph.D. Professor Deputy Dean of Graduate School, Universiti Putra Malaysia.

Date:

Vlll

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.

( LAl SAl HIN )

Date: f/Y/�

IX

TABLE OF CONTENTS

Page

ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ABSTRAK ... . .... . ... ... . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . ... . . . . .. . .. ... . .. .. . IV ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . VI APPROVAL SHEETS ... ... ... ... ... ... ......... ... ... ... ... ... ... ... ... ... Vll DECLARATION FORM . . . ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... IX LIST OF TABLES . .. ... .. . ... ... ... . .. ... ... ... ... . .. ... ... ... . . . ... ... ... . .. ... X111 LIST OF FIGURES . . . ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... XIV LIST OF ABBREVIATIONS ...... ... ... ... ... ... ... ... ... ...... ... ... ... ... ... ... XVll

CHAPTER

I

II

III

INTRODUCTION Statement of Problem . . . . . . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . . .. . . . . .

Objectives of the Study . . . ... . . . . . . . . . . . . . . . .. . . .. .. . .. . .. .

LITERATURE REVIEW Geographical Information Systam (GIS) . . . . . ... . ... ... . . .

Concept of GIS . . . . . . . .. . . . . . . . .. . .. . . . . . . . .. . .. .. . The Benefits and Advantages of Using GIS . . . . . . . . . Arc View - 3D Analyst and Spatial Analyst . . . . . . .. .

Remote Sensing ... .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . .

Advantages of Using Remote Sensing . . . . . . . . . Thematic Mapper (TM) image . . . .. . ... . . . .. . . . .

Watershed Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Model Selection . . . . . . . .. . . . . . . ... . . . . .. . . . . . . . . . . . . Overview of SWAT . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . ... .. . Model Theory ...... . .. . . . . . . ... . . . .. . ... .. . ... .. . . . . . . . . . . Land Phase of The Hydrologic Cycle .. . .. . . . ... . ..... . Erosion . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . . .. . . . . . . . . .

Routing Phase of The Hydrologic Cycle . . . . . . . . .

SW AT - Arc View Interface . . . ... . . . .. . . . . . .. .. . . . . .. .

METHODOLOGY Description of Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Topography . . . ... . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . .

General Geology and Soil .. . . . . . . . . . . . . . . . . . . . . . . . . .

Land Uses/Land Covers . . . . . . . . . . . . . . . . . . . . . . . . .. .

x

1 2 3

4 4 4 6 6 7 9 10 13 14 15 15 17 21 22 25

27 27 30 30 31

IV

V

Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '" . . . ... 31 Water Quality . . . . . . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . '" .. . . . . 32

Data Acquition . . . . . . . . . . . . . . , . . . ... . .. . . . . .. ... . . . . . . . .. . . . 32 Data Processing and Management . . . . . . . . . . . . . . . . . . '" .. . . . . 34 SWAT Project Development . . . . . . . . . . . . . . . . . . . .. . . . . . . '" . .. . . . 38 Model Calibration and Simulation . . . . . . . . . . . . . . . . . . '" . .. . .. 39 Methods for Analyzing Results . . . . . . . . . . . . . . . . . . .. . . . . . . . . " .. . . 40

Theil's Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . '" . . . . . . 40 Correlation Analysis . . . .. . . . . .. . . . . . . . . . . . . . . . . . " ... .. . 41

Overall Procedure . . . ... . . . . . . . . . . . . . . . . .. . .. . . . ... ... .. . . .. . .. 42

RESULTS AND DISCUSSION ... .. . '" . . , . . . . . . ' " . . . . . .

GIS Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Digital Map . .. . .......... . .. . . . . . .. ' " . . . . . . . . . . " . . . . . .

Grid Maps . . .. . . .. . . . . .. . . . . . . . . . . ' " . . . . . . . . . '" . . . . . .

Arc View Database Tables .. . . . . ' " . . . . . . .. . ' " . . . . . .

Raster Outputs ........ . .... " .. . . . . . . . . . . . . . . . . . . . ' " . . . . . .

Feature Extraction . . . ' " . . . . . . . . . '" . . . . , . . . . ' " . . . . . .

Enhancement .. . . . . .. . .. . . .. . . . . . . ... ... .. . . ..... .. . . . . .. .

Land Use Identification . . . . .. ' " . . . . . . . . . ' " . . . . . .

Land Use Classification Supervised Classification . . . . . . ' " . . . . . . . . . '" . . . . . .

SWAT Databases and Data Estimation ... ... . .. ... ... .. . SWAT Database - User Soils .. . .. . ... ... . .. ........... .

SWAT Database - User Weather Station .. . ..... .

SWAT Database - Land Coverl Plant Growth . . . . . . . .

Historical Data Analyses . . . ... . . . . .. ... '" . . . . . . . . . . . . . . . . . .

Rainfall-Runoff Ratio and Basin Water Balance . . . . .

Relation Between Discharge and Sediment ... ...... . SW AT Project . . . .. . .. . . . . ... . . . . . . . .. '" . . . . . , . . . '" . . . . . , Model Results and Dicussion .. . ' " . .. . . . . . . . . . . .. . . . . . . . . . . . . . . .

Statistical Analyses . " . . . . . . . . . ' " . . . . .. . . . . . . ... . . . . . . '" .. . . . .

Effect of Land Use Changes on Streamflow and Sediment Load

CONCLUSIONS AND RECOMMENDATIONS Summary .. . ... . .. ...... ... ...... . . . ... . . . ' " .. . . . . . . . ' " . , . . .. . Conclusions . . . . . . . , . . " . . . . . . . . . '" . . , . . . . . . ' " . . . . . . . . . . . . . . . . .. .

Recommendations

XI

44 44 44 47 50 55 55 55 58 58 58 70 70 72 73 75 75 78 83 89 100 101

104 104 105 106

BIBLIOGRAPHY 107

APPENDICES 114

BIODATA OF THE AUTHOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

xii

Table

2.1

2.2

3.1

3.2

3.3

4.1

4.2

4.3

4.4

LIST OF TABLES

Characteristic of Landsat Thematic Mapper (TM) Data

Advantages and limitations of model reviewed

Background of the river basin . . . . . . . . . ... . . . . . . . " . . . . .. .. . . . . . . . . . . . . . '"

Types of data and their sources

Categorization of model application results using correlation analysis

ArcView database tables and their functions '" . . . . . . . . . . . . . . . . . . . . . ' "

Water balance calculation for the Upper Bemam Basin

Subbasins delineated, coverage area, and main reach draining each subbasin . . . . . . . . . . . . . . , . . . '" . . . .. . . . . . . . .. . . . . . . . . . . .

Land use infonnation derived from Landsat TM images

Page

12

14

28

33

42

52

76

85

89

4.5 Observed and calibrated results of the Upper Bernam Basin for year 1998 . . . . . . . . . . . . . . . . . . . . . . .. . . . . , . . . . . . . '" . . . . . . . . . . . . . . . . . . . . . . .. . 91

4.6 Observed and predicted results of the Upper Bemam Basin for year 1993 . . . . . . . . . . . . ... .. . .. . .. . . . . . . . . . . . . . '" .. . . . . . . . . . . . . . . . . . . . '" . 94

4.7 Observed and predicted results of the Upper Bemam Basin for year 1995 . . . . . . . . . . .. '" . . . . . . . . . . . . . . . . . . ... '" . . . .. . . . . . . . . . . . . . . . . . . . . . 97

4.8 Statistical analyses of modeling results for the Upper Bemam Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 101

4.9 Relationship between open area and streamflow rate for the month the satellite imageries were taken . . . . . . . . . . , . . . . . . . '" . . . . . . . . . . . . . . . . . . . . . .. . . 101

4.10 Relationship between open area and sediment loading rate for the month the satellite imageries were taken . . . . . . . . . '" . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

xiii

Figure

2.1

2.2

2.3

2.4

2.5

3.1

3.2

3.3

3.4

3.5

3.6

4.1

4.2

4.3

4.4

4.5

4 .6

4.7

LIST OF FIGURES

Spatial data

Relative reflectance of typical ground cover types as a function of wave length . . . . . . . . . . . . ' " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Land phase of the hydrologic cycle

Arc View View menu and tool bars

SWAT Watershed View menu and tool bars . . . . . . . . . . . . . . . . . . . . . . . . . . .

Map showing location of study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sequence of Landsat TM image processing . . . . . . . . . . . . . . . . . . . . . . . . . . .

Data management using WDMUtil . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .

SW AT databases

Customized Watershed menu in Arc View interface for SWAT project development . . . ' " . . . ' " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Schematic diagram showing overall procedure of the study . . . . . . . . . .

Topographic relief of the Upper Bemam Basin

Top view of Triangulated Irregular Network (TIN) representing the project area . . . . . . . . . . . . ' " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Digital Elevation Model (DEM) for the Upper Bemam Basin

Grid map representing soil types of the Upper Bemam Basin

Classified Land use grid map derived from Landsat TM image (Date: 28/1/98) . . . ' " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Samples of location tables and look up tables

Samples of data tables . . . ' " . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

XIV

Page

5

11

16

25

25

29

35

37

37

38

43

45

46

4 8

49

51

53

54

4.8 Landsat TM Image befo re enhancement 56

4.9 Landsat TM image a fte r enhancement 57

4.10 Land use identification based on Landsat TM image band 4, 5 and 3 59

4.11 Si gnatu re selection

4.12 Recode classes

4.13 Classified land use map de rived from Landsat image

4.13a de rived f rom Landsat image (Date : 26 Feb 1993 )

4 .13b de rived from Landsat image ( Date : 14 Oct 1995)

4.13c de rived f rom Landsat image (Date : 28 Jan 1998)

60

61

63

64

65

4.14 Sampling points fo r classified raste r image accu racy assessment . . . . 67

4.15 Refe rence values fo r gene rated sampling points

4.16 Classification accu racy assessment repo rt

68

69

4.17 SWAT database - Use r Soils . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . 71

4.18 SWAT database - Use r Weathe r stations

4 .19 Ave rage annual rainfall f rom rep resentative stat ions and runoff fo r

73

the Uppe r Bemam Basin upst ream of S KC B ridge gauging station 77

4.20 Ave rage annual runo ff/rainfa ll ratio fo r the Uppe r Bemam Basin upst ream of S KC B ridge gauging station . . . . . . . . . . . . . . . . . . .. . . . . .. .. 77

4.21 Sedimentation rate at S KC B ridge station 81

4 .22 Sedimentation rate at S KC B ridge station plotted by month of the yea r 82

4 .23 Wate rshed, subbasins and st ream de fin ition . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 84

4 .24 Subbasins delineat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

4.25 Land use /soil combination used to c reate multiple HRUs fo r each subbasin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

xv

4 .26 Weathe r and rive r mon ito ring stat ions ava ilable in the p ro ject a rea . . . 88

4 .27 Compa rison of ra infall . st re amflow and sed iment load of the Uppe r Bemam Bas in fo r yea r 199 8 . .. . . . . . ... . . . . . . . . . . . . . . . . ... . .. . . . . . . . . . '" . . . 92

4.28 Mass cu rve of st ream flow and sed iment load of the Uppe r Bemam Bas in fo r yea r 1998 . . . .. , . . . ... .. . . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . 93

4.29 Compa rison of ra infall . st reamflow and sed iment load of the Uppe r Bemam Bas in fo r yea r 1993 . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . 95

4.30 Mass cu rve of st ream flow and sed iment load of the Uppe r Bemam Bas in fo r yea r 1993 . . . . . , . . . . . . . . . . . . . . . . . . . . . .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . 96

4 .31 Compar ison of ra infall . st re amflow a nd sed iment load of the Uppe r Bemam Bas in fo r yea r 1995 . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 9 8

4.32 Mass cu rve of st ream flow and sed iment load of the Uppe r Be mam Bas in fo r yea r 1995 . . . . . . . . . . . . . . . . . . . . . .. . .. . . . . . . . . . . . . . '" . , . '" . . . . . . . . . 99

Xv,

P

3D

ADP

A LB

AWC

B ARE

B D

C

C H D

CH K

C H L

C H N

CH W

C LA Y

C N2

C 02

COEF

DEWPT

FRSE

GPS

HHMX

HRU

HRU FR

HW Q

H YDGRP

K

LIST OF ABBREVIATIONS

Co rrelation coefficient

3 Dimens ional

Ave rage daily p recipitation in month

Moist soil albedo

Available wate r capacity of soil laye r

4 digit land use class - ba re land

Moist bulk density of soil laye r

USLE c rop management facto r

Ave rage depth of main channel

Effective hyd raulic conductivity in t ributa ry channel alluvium

Length of main channel

Manning 's "n " value fo r t he t ributa ry channel

Ave rage width of t ributa ry cha nne ls

Clay content of soil laye r

SCS cu rve numbe r fo r moistu re condition II

Ca rbon dio xide concent ration

Skew coefficient of daily p recipitation in month

Ave rage dew point tempe rat ure in month

4 digit la nd use class - fo rest

Global Posit ion ing System

Ma ximum 0 .5 hou r rainfall in month fo r the yea rs with available

data

Hyd rologic Response Unit

F raction of total wate rshed a rea contained in HRU

Hyd rologic and wate r quality

Soil Hyd rologic group .

Satu rated hyd raulic conductivity of soil laye r

XVII

OILP

OVN

Pcp98FT U

Pcp98LTL

Pcp98L KY

Pcp98PTM

PCP D

P RB D

PRB W

RUBB

SA ND

SC RB

SCS

S DP

Sg

S ILT

SLOPE

SLSOIL

SLSUBBS N

SOL

tmp98 tmx

tmp98tmn

T MPCVT

T MPMX

T MPMN

TIN

U

URBN

USLE K

4 digit land use class - oil palm

Manning 's "n " value fo r ove rlan d flow

daily p recipitation fo r 1998 reco rded at station Felda T rolak Uta ra

Daily p recipitation fo r 1998 reco rde d at station La dang T rolak

Daily p recipitation fo r 1998 reco rde d at station La dang Ketoyang

Daily p recipitation fo r 1998 reco rded at station Pekan Tanjung

Malim

Ave rage numbe r of days of p recipitation in month

P robability of wet day following d ry day in month

P robability of wet day following wet day in month

4 digit land use class - rubbe r

San d conten t of soi l laye r

4 digit land use class - sc rub

So il Conser vation Se rvice

Standa rd deviation fo r daily p recipitat ion in month

Sungai / rive r

Silt content of soi l laye r

Ave rage slope steepness

Slope length fo r late ral subs urface flow

Ave rage slope leng th

Ave rage daily sola r radiation fo r month

Daily ma ximum tem perat ure recor de d fo r yea r 1998

Daily minimum tem pera ture reco rded fo r year 199 8

Coe fficient of va riation fo r the ave rage tem peratu re fo r month

Ave rage ma ximum ai r tem peratu re fo r month

Ave rage minimum ai r tem peratu re fo r month

T riangulated Irregula r Netwo rk

Theil 's coe fficient

4 digit land use class -"u rban a rea

USLE equation soil e ro dibility (K) facto r

XVlll

W ATR

W DM Util

W IND AV

Z

4 d ig it lan d use class - wate r bo dy

Wate rshed Data Management Uti lity

Ave rage wind speed in month

Depth of a ce rtain soil ho ri zon / laye r

xix

1

CHAPTER!

INTRODUCTION

In recent yea rs , Malaysia has unde rgone ve ry rapid development with popula tion

g rowth, u rbani zation, e xpansion of a gricult ure, logging activities, and indust riali za tion.

These changes have caused comple x envi ronmental p roblems and the most affected

natu ral resou rce is wate r.

Rising concern ove r the deg radation of the envi ronment, such as ou r rive r wate r quali ty,

has resulted in an inc rease m resea rch on the identification and study of envi ronmental

p roblems. The rapid rise in the volume and quantity of data collected, and massive

changes in technical capabilit y have facilitated the development of Geog raphical

Info rmation System (G IS) and remote sensing to handle the div ersi ty of info rmation

involved.

Inhe rent in the solution of the above p roblem and many envi ronmental p roblems is the

need to b ring togethe r dispe rsed data sets. The comple xity and si ze of these databases

make the requi rement fo r application of G IS and remote sensing technology all the mo re

necessa ry. The advantage of holding all the info rmation to gethe r is to allow sea rches

and que ries to be made on a combination of info rmation so that effec tive fo rmulation

and implementation of any st rategies , policies and plans which a re highly dependent on

accu rate, comp rehensive and timely info rmation can be achieved.

2

Statement of the Problem

In the study of watershed problems, it has been found that most of the

distributed/physically based hydrologic and water quality (HWQ) model from developed

countries are not suitable for local use due to different atmospheric conditions and

availability of data. Another fact is that most of those models are too complex and thus,

too difficult to use or not user friendly. In addition, very few of them are applicable to

basin scale study. Knowing these, a simple GIS interface physically based and

computationally efficient distributed model has been chosen for evaluation. By

confirming the effectiveness of the selected model in the tropical watershed

management, it provides an alternative to potential users such as hydrologists,

environmentalists, policy makers and etc.

Through data overlaying technique, classified remote sensing data has been applied in

this study. Necessary data set representing hydrology, weather, soil, elevation and

surface characteristic were integrated in a GIS in tabular, vector and grid formats. By

bringing key data and analytical components together "under one roof', it is hoped that

the problems of lack of integration, limited coordination, and time-intensive execution

typical of the more traditional assessment tools can be overcome. Similar studies in the

future will become easier in terms of time, effort and cost saving to acquire and manage

temporal as well as spatial data.

3

With the ability of a selected model to p redict o r gene rate s imulated rainfall, st ream flow

and wate r quali ty from a rive r basin , these p rovide quanti tative means to test alternatives

and con trols befo re e xpensive measu res a re implemented. These also enable effective

planning and decision making of any development of pollution con trol st rategies, plan o r

policy fo r bette r wate r management of a humid t ropical rive r basin.

It is envisaged that the database gene rated and the wate r quali ty output of the simulation

as well as maps, cha rts, o r tables gene rated can be used to advance the knowledge on the

e xisting envi ronment d urin g the s tudy pe riod. This is to allow compa rison w ith the

p resent o r fu ture situation of the rive r basin and also allow a continual t rend analysis fo r

any fu rthe r simila r studies.

Objectives of the Study

In view of the issues and p roblems discussed above, this study aims to evaluate the

e ffectiveness of a GIS inte rface physically based hyd rologic and wate r q uali ty (HW Q )

model in p redicting daily s tream flow and wate r quality from a t ropical rive r basin.

The specific objectives :

1. To ca rry out a p relimina ry resea rch into combining remote sensing data , GIS and

a wate rshed model fo r hyd rolog ic evalua tion p urposes �

2 . To evaluate the effectiveness of selected model in a rive r basin using remote

sensing data and GIS-de rived inputs.

4

CHAPTER II

LITERATURE REVIEW

Geographical Information System (GIS)

G IS in the gene ral conte xt of the env ironmental appl icat ions can be defined as a

compute r-ass isted and integrated env ironment fo r geograph ical data c reat ion , sto rage

and ret rieval, management, man ipulat ion, anal ys is and d isplay (No rl in Jaafa r, 1997 ). It

is able to p rov ide effect ive and e ffic ient funct ions fo r handl ing la rge spat ial database and

a ids data invento ry, management, p roblem solv ing and dec is ion mak ing.

Concept of GIS

Acco rd ing to Holdstock (1998), one of the wo rld 's lead ing G IS so ftwa re vendo rs

o rgan izes data in such a way that they can be env is ioned as d ig ital laye rs o r cove rages of

info rmat ion. Each cove rage is reg iste red to the same common map base ; each has a

d ist inct type of featu re such as po ints, polyl ines o r polygons . The GIS sto res the spat ial

data and att ribute data. A cove rage rep resents a s ingle theme, such as land -use

( polygon ) , so ils type (polygon ) , rive rs (l ine ) , roads (l ine ) , and bu ild ings (po int ) as shown

in F ig ure 2 .1.

5

F igu re 2.1: Spa tial Da ta (Sou rce : Da vid A. Ho lds tock , G IS/GP S Direc to r, In stitu te fo r T rans porta tion Resea rch and Educa tion (ITRE), No rth Ca rolina Sta te Un ive rs ity)

universiti putra malaysia application of swat … · 2016-08-04 · menunjukkan bahawa swat secara...

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