Luận văn thạc sĩ application of swat model to assess the impact of land use changes on stream

THAI NGUYEN UNIVERSITY

UNIVERSITY OF AGRICULTURE AND FORESTRY

DINH NGOC HUAN

TOPIC TITLE: “APPLICATION OF SWAT MODEL TO ASSESS THE

IMPACT OF LAND-USE CHANGES ON STREAM DISCHARGE IN

NGHINH TUONG WATERSHED, THAI NGUYEN PROVINCE”

BACHELOR THESIS

Study Mode: Full-time

Major: Bachelor of Environmental Science and Management

Faculty: International Training and Development Center

Batch: 2010 - 2015

Thai Nguyen, January 2015

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DOCUMENTATION PAGE WITH ABSTRACT

Thai Nguyen University of Agriculture and Forestry

Degree Program Bachelor of Environmental Science and Management

Student name Dinh Ngoc Huan

Student ID DTN1054110040

Thesis Tittle Application of SWAT model to assess the impact of

land-use changes on stream discharge in Nghinh

Tuong watershed, Thai Nguyen Province

Suppervisor (s) Phan Dinh Binh, Ph.D.

Abstract:

The purpose of this research is to implement “Soil and Water Assessment Tool

(SWAT)” model and GIS to evaluation, assessment impact of land-use changes

on stream discharge in Nghinh Tuong watershed (riverhead Cau river watershed)

in Northern Viet Nam. The watershed were cover by 56% forestry land, 30%

agricultural land, and remain for others. Stream discharge observed data 2002 -

2012 were used for calibration (2002 - 2007) and validation (2008 - 2012). The

result shown that two coefficients (NSE and PBIAS) to evaluate model

performance were 0.76 and 6.54% for calibration period and 0.87 and 4.74%,

respectively. Stream discharge strongly depends not only on quantity of

precipitation but also on land use change. Through the scenario 1, agricultural

land (corn, orchard and tea) increases 9782.67 ha (2.45%), meanwhile forest

(forest-mixed) decreases 1091.77 ha (2.75%) as compared to baseline scenario.

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Additionally, precipitation increases 3.74% in mean wet season, but decreases

0.5% in mean dry season with respect to baseline period. SWAT model was able

to simulate stream discharge and sediment yield for Nghinh Tuong watershed

successfully not only for Baseline scenario but also for Scenario 1. In brief,

SWAT proves its ability in simulation stream discharge and sediment yield in

watershed level. It is a useful tool to assist water quantity and quality

management process in Nghinh Tuong watershed.

Keywords: Key words: stream discharge, watershed, GIS, SWAT

model, scenario

Number of pages: 50

Date of Submision : January 15, 2015

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ACKNOWLEDGEMENT

First and foremost, I wish to express my sincere thanks to the boards of

Thai Nguyen University of Agriculture and Forestry, Dean of Faculty Natural

Resources Management, Department of Remote sensing and Surveying of Thai

Nguyen University of Agriculture and Forestry for providing me all the

necessary facilities and all the teachers who built me the scientific knowledge to

complete this research. In particular, I would like to thank my principal research

adviser Dr. Phan Dinh Binh who guided me wholeheartedly when I implement

this research project.

I place on record, my sincere gratitude to all staffs, government and

people in Nghinh Tuong commune Vo Nhai district and Van Lang commune

Dong Hy district, Thai Nguyen province for their expert, valuable guidance

and generous support to our project.

Finally yet importantly, I take this opportunity to express our deepest

appreciation to our families, relatives, friends and fellow students in class of

K42-Advanced Education Program who encouraged and supported me

unceasingly and all who, directly or indirectly, have lent their helping hand in

this venture.

Thank you very much!

Thai Nguyen, January 15, 2015

Student

Dinh Ngoc Huan

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TABLE OF CONTENTS

ACKNOWLEDGEMENT ................................................................................. iv

TABLE OF CONTENTS .................................................................................... v

LIST OF TABLES ............................................................................................ viii

LIST OF FIGURES ............................................................................................ ix

LIST OF ABBREVIATIONS ............................................................................. xi

Part 1: INTRODUCTION .................................................................................. 1

1.1. Research rationale .......................................................................................... 1

1.2. Research’s objectives ...................................................................................... 1

1.3. Research questions and hypotheses ................................................................ 3

1.4. Limitations ...................................................................................................... 3

1.5. Definitions ...................................................................................................... 3

Part 2: LITERATURE REVIEW ...................................................................... 5

2.1. Research situation ........................................................................................... 5

2.2. Soil and Water Assessment Tool (SWAT) Model ........................................... 6

2.2.1. Concept of SWAT ........................................................................................ 6

2.3. SWAT Theory ................................................................................................. 8

2.3.1. SWAT hydrologic component ...................................................................... 8

2.3.2. The land phase of the hydrologic cycle ....................................................... 8

2.3.2.1. Climate...................................................................................................... 9

2.3.2.2. Hydrology ................................................................................................. 9

2.3.3. Routing phase of the hydrologic cycle ...................................................... 10

2.3.3.1. Routing in river ....................................................................................... 10

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2.3.3.2. Routing through reservoirs ..................................................................... 10

2.3.3.3. Sediment routing .................................................................................... 10

2.4. Component processes in model (Neitsch et al., 2005a) ............................... 11

2.4.1. Surface runoff ............................................................................................ 11

2.4.2. Underground Flow ..................................................................................... 13

2.4.2.1. Lateral subsurface flow .......................................................................... 13

2.4.2.2. Underground flow ................................................................................... 13

2.5. SWAT sediment component (Neitsch et al., 2005a) .................................... 14

2.5.1. The Modified Universal Soil Loss Equation (MUSLE)............................ 14

Part 3: METHODS ............................................................................................ 16

3.1. Materials ....................................................................................................... 16

3.1.1. Description and topography ...................................................................... 16

3.1.2. Climatic characteristics ............................................................................. 18

3.2. Methods ........................................................................................................ 19

3.2.1. Watershed delineation ............................................................................... 19

3.2.2. Soil classification and soil physical characteristics ................................. 19

3.2.3. Land cover classification .......................................................................... 20

3.3. SWAT model ................................................................................................. 20

3.4. SWAT model performance evaluation ......................................................... 22

Part 4: RESULTS ............................................................................................. 25

4.1. Overview of Nghinh Tuong basin ................................................................ 25

4.2. Preparation input data .................................................................................. 26

4.2.1. Climatic parameters ................................................................................... 26

4.2.1.1. Precipitation ............................................................................................ 29

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