EFFECTS OF CONVERSION OF RANGELAND TO DRY FARMING … fileuniversiti putra malaysia effects of conversion of rangeland to dry farming on surface runoff, soil erosion and sediment yield

UNIVERSITI PUTRA MALAYSIA

EFFECTS OF CONVERSION OF RANGELAND TO DRY FARMING ON

SURFACE RUNOFF, SOIL EROSION AND SEDIMENT YIELD IN KARDEH

DRAINAGE BASIN, IRAN

FARID SAEIDYAN

FPAS 2012 14

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BY

FARID SAEIDYAN

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,

in Fulfillment of the Requirement for the Degree of Doctor of Philosophy

October 2012

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DEDICATION

To my dear wife and best friend, Shideh and our son, Pouya

Without her support, I could not get through such grueling task.

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Abstract of the thesis presented to the Senate of Universiti Putra Malaysia in

fulfillment of the requirement for the degree of Doctor of Philosophy




By

FARID SAEIDYAN

October 2012

Chairperson: Associate Professor Wan Nor Azmin B Sulaiman, PhD

Faculty: Environmental Studies

Land use/cover changes may affect hydrological properties, soil erosion and sediment

yield of a basin. In arid and semi-arid regions, these changes mostly appear as

conversion of rangelands to dry farming. The main research question is: what is the

effect of such conversion on hydrologic and soil characteristics of the basin. This

research evaluates the trend of converting rangelands to dry farming in Kardeh

Drainage Basin, Iran and its effects on surface runoff, soil erosion and sediment yield.

Hydrologic simulations based on different design rainfall and the impacts of different

scenarios of vegetation conditions on flood peak were assessed. Land use and

vegetation maps 1970 and 2006 were prepared using aerial photographs and satellite

images. Rainfall-Runoff relations and flood routing in the channel were obtained by

using curve number and Muskingum methods respectively in HEC-HMS model. The

effect of temporal distribution of rainfall on hydrologic simulation was studied.

Future flood simulations were evaluated based on six future land use scenarios of

vegetation cover condition ranging from highly vegetated cover (good) to sparsely

vegetated condition (poor). The Erosion Potential Method (EPM) was used to

evaluate the total annual sediment discharge for the basin. Multiple regression

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approach was use to identify the most effective factors on the sediment yield of the

sub basin.

The results of the study showed a drastic change of land use between 1970 and 2006

especially in the increment of dry land (91%) and reduction of rangeland (about

13%). In the same period, the predicted peak discharge at sub basin level appeared to

increase more than the runoff volume. In addition, runoff concentration time and lag

time was reduced as well as time to peak of hydrograph. The simulation output

indicated that for a two year rainfall return period, changes of peak discharge

increased significantly (70%). While for a rainfall return period of 100 years, the

changes of peak discharge decreased (41%).

In future land use scenarios, simulations of 1 poor range condition to good range

condition, peak discharge decreases drastically; however, the effects diminished as

design rainfall return period increased.

Erosion and sediment yields increased about 82% from 1970 to 2006. Multiple

regression analysis showed that 70% of the changes in sediment yield in the year

2006 are due to the effects of increase in dry farming area (R2= 70%, α < 0.05).

The results point to the fact that converting rangelands to dry farming in an arid and

semi-arid region such as the Kardeh Drainage Basin, leads to many negative effects

on hydrological properties, including increase in runoff coefficient, peak discharge,

runoff volume, and decrease in concentration time, lag time and time to peak. The

land use change was the major contributing factor to the increase of sediment yield in

the basin.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia

sebagai memenuhi keperluan untuk ijazah Doktor Falsafah

KESAN PENUKARAN KAWASAN RAGUT KEPADA PERTANIAN KERING

KE ATAS AIR LARIAN PERMUKAAN, HAKISAN TANAH DAN HASIL

ENDAPAN DALAM LEMBANGAN SALIRAN KARDEH, IRAN

Oleh

FARID SAEIDYAN

Oktober 2012

Pengerusi: Professor Madya Wan Nor Azmin B Sulaiman, PhD

Fakulti: Pengajian Alam Sekitar

Perubahan guna/litupan tanah boleh menjejaskan sifat hidrologi, hakisan

tanah dan hasil endapan sesebuah lembangan. Di kawasan-kawasan yang

gersang dan separa gersang perubahan ini kebanyakannya muncul kerana

penukaran kawasan ragut kepada pertanian kering. Persoalan kajian yang

utama ialah apakah kesan bagi penukaran itu kepada ciri-ciri hidrologi dan

tanah lembangan. Kajian ini menilai tren pertukaran bagi kawasan ragut

kepada pertanian kering dalam Lembangan Saliran Kardeh, Iran dan

kesannya ke atas air larian, hakisan tanah dan hasil endapan. Simulasi

hidrologi berdasarkan hujan rekabentuk yang berbeza dan impak bagi

senario keadaan tumbuhan berbeza ke atas puncak banjir telah ditaksir. Guna

tanah dan peta tumbuhan 1970 dan 2006 disediakan menggunakan foto udara

dan imej satelit. Hubungan hujan-air larian dan penghalaan banjir dalam

saluran telah diperolehi masing-masing menggunakan kaedah nombor

lengkung dan Muskingum dalam model HEC-HMS. Kesan agihan masa

hujan ke atas simulasi hidrologi telah dikaji. Simulasi banjir masa hadapan

telah dinilai berdasarkan enam senario guna tanah masa hadapan bagi

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keadaan bertutup tumbuhan bermula dari bertutup tumbuhan tinggi (baik)

hingga bertumbuhan jarang (buruk). Kaedah Hakisan Potensi (EPM)

digunakan untuk menilai discas jumlah tahunan endapan untuk lembangan

itu. Pendekatan regresi berbilang digunakan untuk mengenal pasti faktor

yang paling berkesan ke atas hasil endapan sub lembangan itu.

Keputusan kajian menunjukkan perubahan guna tanah yang drastik antara

1970 dan 2006 terutamanya dalam pertambahan tanah kering (91%) dan

pengurangan kawasan ragut (kira-kira 13%). Dalam tempoh yang sama,

discaj puncak yang diramalkan pada peringkat sublembangan muncul

meningkat lebih daripada isipadu air larian. Di samping itu, masa tumpuan

air larian dan masa susulan telah dikurangkan di samping masa memuncak

hidrograf. Output simulasi menunjukkan bahawa untuk kala kembali hujan

2-tahun perubahan discaj puncak meningkat dengan ketara (70%). Manakala

bagi kala kembali 100 tahun hujan perubahan discaj puncak menurun (41%).

Dalam senario masa hadapan guna tanah, simulasi bagi 1 julat berkeadaan

buruk kepada julat berkeadaan baik, puncak discaj menurun dengan drastik,

namun kesannya berkurangan apabila kala kembali hujan rekabentuk

meningkat.

Hakisan dan hasil endapan meningkat kira-kira 82% daripada 1970 ke 2006.

Analisis regresi berbilang menunjukkan bahawa 70% daripada perubahan

dalam hasil endapan dalam tahun 2006 adalah kerana kesan yang meningkat

dalam pertambahan kawasan perladangan kering (R2 = 70%, α <0.05).

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Keputusan itu menumpu kepada fakta bahawa penukaran kawasan ragut kepada

pertanian kering di kawasan gersang dan separa gersang seperti Lembangan Saliran

Kardeh menghasilkan banyak kesan negatif ke atas sifat hidrologi, termasuk

peningkatan pekali air larian, discaj puncak, isipadu air larian, dan penurunan dalam

masa tumpuan, masa susulan dan masa memuncak. Perubahan guna tanah didapati

menjadi faktor penyumbang utama kepada peningkatan hasil endapan di lembangan

itu.

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ACKNOWLEDGEMENT

I thank GOD for all His blessings on me and thank Him for giving me courage and

strength to finish my study. It is understood that human beings cannot repay one

another enough. Hence, it is better to request Almighty Allah to reward the person

who did a favor and to give him the best.

The completion of this thesis would have not been possible without the support and

cooperation of many individuals and some institutions. I am very grateful to all of

them.

I wish to thank Dr. Wan Nor Azmin Sulaiman for supervisory my study. He has

guided me throughout the preparation of the thesis. His comments and suggestions on

the structures and contents of the thesis have considerably improved its quality and

readability. I learned a lot from his style of supervision and I really benefited from his

knowledge and considerable experience in watershed management.

Many thanks to Professor Majid Yasoori and Dr. Firuz Ramli, members of my

supervisory committee who scrutinized my thesis, and for all the nice discussions we

had, and for their invaluable comments and suggestions.

Many thanks go to the Head and technical staff of Environmental Science

Department in UPM. Special thanks to the Director of the Research Center for

Agriculture and Natural Resources of Khorasan Razavi Province, Dr. Rangavar. I am

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thankful to Mr. Hassan Tabarai and all my other colleagues in the Khorasan Razavi

Planning and Management Organization.

Finally, I would like to thank my wife and my son for their sacrifices and efforts

during my study especially when I was not in Iran and they were alone. By no means

could I ever be able to repay them. They should know that my thesis could never

have come into being, without them as my source of inspiration and encouragement.

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I certify that a Thesis Examination Committee has met on 10 October 2012 to

conduct the final examination of Farid Saeidyan on his thesis entitled " Effects of

Conversion of Rangeland to Dry Farming on Surface Runoff, Soil Erosion and

Sediment Yield in Kardeh Drainage Basin, Iran " in accordance with the Universities

and University College Act 1971 and the Constitution of the Universiti Putra

Malaysia [P.U. (A) 106] 15 March 1998. The committee recommends that the

candidate be awarded the Doctor of Philosophy.

Members of the Examination Committee were as follows:

Ahmad Makmom bin Abdullah, PhD

Associate Professor

Faculty of Environmental Studies

Universiti Putra Malaysia

(Chairman)

Zelina binti Zaiton Ibrahim, PhD

Associate Professor



(Internal Examiner)

Mohd Amin bin Mohd Soom, PhD

Professor

Faculty of Engineering


(Internal Examiner)

Suhas Pralhad Wani, PhD

Professor

International Crops Research Institute for the Semi-arid Tropics (ICRISAT)

India

(External Examiner)

SEOW HENG FONG, PhD

Professor and Deputy Dean

School of Graduate Studies


Date: 21 March 2013

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been

accepted as fulfillment of the requirement for the degree of Doctor of Philosophy.

The members of the Supervisory Committee were as follows:

Wan Nor Azmin bin Sulaiman, PhD

Associate Professor



(Chairperson)

Firuz Ramli, PhD

Associate Professor



(Member)

Majid Yasoori, PhD

Professor

Ferdowsi University

Mashhad, I.R.Iran

(Member)

BUJANG BIN KIM HUAT, PhD Professor and Dean

School of Graduate Studies


Date:

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DECLARATION

I declare that the thesis is 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 Universiti Putra Malaysia or at any

other institutions.

FARID SAEIDYAN

Date: 10 October 2012

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TABLE OF CONTENTS

Page

DEDICATION ii

ABSTRACT iii

ABSTRAK v

AKNOWLEDGEMENTS viii

APPROVAL x

DECLARATION xii

LIST OF TABLES xviii

LIST OF FIGURES xxv

LIST OF SYMBOLS AND ABBREVIATIONS xxxi

CHAPTER

1 INTRODUCTION 1

1.1 Flood, erosion and sediment yield 1

1.2 Scope of the problem 5

1.3 Hypotheses 6

1.4 Research objectives and approach 6

1.5 Significance of study 11

2 LITERATURE REVIEW 13

2.1 Land use definition 13

2.1.1 Types of land use 13

2.1.2 The land use situation in Iran 14

2.2 Flood definition 17

2.2.1 Conversion of precipitation to runoff 17

2.2.2 The flood hydrograph and its different sections 19

2.2.3 The factor effecting on the hydrograph shape 21

2.2.4 The effects of land use and vegetation cover changes 25

on the drainage basin flooding

2.2.5 Approaches for investigation the effects of changing in 31

vegetation cover on the hydrological reaction in a basin

2.2.6 The hydrological models of precipitation-runoff simulation 35

2.2.7 Runoff routing 42

2.2.8 The application of geographic information system 44

(GIS) in the hydrological models

2.2.9 Flooding characteristics in Iran 48

2.3. Erosion definition 52

2.3.1 Different types of water erosion 52

2.3.2 Factors contributing to soil degradation and erosion 53

in the world

2.4. Sediment definition 55

2.4.1 Sediment yield 55

2.4.2 Sediment yield origins 56

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2.4.3 The factors affecting on sediment yield in the drainage 58

basins

2.4.4 Soil degradation and erosion in Iran 64

2.5. Summary of chapter 65

3 THE STUDY AREA 68

3.1 Description of the study area 68

3.2 Physiography 69

3.2.1 Drainage network 70

3.2.2 Preparation of drainage basin map and delineating 72

basin and sub-basins boundary

3.2.3 Channel density 76

3.2.4 Shape of the drainage basin 76

3.2.5 Preparation of Digital Elevation Model (DEM) 77

3.2.6 Basin slope 82

3.3 Climate 85

3.3.1 Climatology station network 87

3.4 Geology 91

3.5 Pedology 96

3.5.1 Investigation of land resources 96

3.6 Hydro meteorological networks 99

3.6.1 Mareshk station 99

3.6.2 Al station 99

3.6.3 Koshkabad station 100

3.7 Vegetation cover 102

3.8 Agriculture land use 104

3.9 Demography 107

4 EVALUATION OF LAND USE CHANGE FROM RANGELAND 109

TO DRY FARMING ON FLOOD EVENTS

4.1 Introduction 109

4.2 Methodology 110

4.2.1 Preparing the vegetation and land use map in 2006 116

4.2.2 Preparing the vegetation and land use map in 1970 126

4.2.3 The investigation of changes in land use between 127

years 1970-2006

4.2.4 Preparing of the soil hydrological groups map 127

4.2.5 CN determination of different land uses in each sub basins 128

4.2.6 Investigation trend of flood occurrence in Kardeh 133

drainage basin

4.2.7 Selection of observed flood hydrograph 138

4.2.8 Collection of total daily rainfall recorded in the stations 139

4.2.9 Determining spatial distribution of rainfall in sub basins 140

4.2.10 Determining temporal distribution of rainfall in sub basins 143

4.2.11 Calculation of concentration time (Tc) for sub basins 148

4.2.12 Method on calculation of lag time in sub basins 149

4.2.13 Flood routing in the river of the study area 150

4.2.14 HEC- HMS model specifications 153

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4.2.15 Data input to HEC-HMS model 157

4.2.16 Analysis of the model sensitivity to the changes in 166

parameters of the study area

4.2.17 Selection of model calibration for the study area 168

4.2.18 Selection of model validation for the study area 170

4.2.19 Using the model 171

4.2.20 Calculation of runoff coefficient 172

4.2.21 Model implementation in two periods after 172

calibration model

4.2.22 Determination of the design rainfall 173

4.2.23 Model implementation in two periods (1970 and 2006) 177

for design rainfall

4.2.24 Changes in concentration time, lag time and time 177

of peak hydrograph (1970 and 2006)

4.3 Results 178

4.3.1 Land use map in 2006 for the study area 178

4.3.2 Land use map in 1970 for the study area 180

4.3.3 Changes in land use between the years 1970-2006 182

4.3.4 Soil hydrological groups map for the study area 185

4.3.5 Curve number maps for the basin 186

4.3.6 Spatial distribution of rainfall in basin area 206

4.3.7 Temporal distribution of rainfall in basin rainfall 212

4.3.8 Concentration time (Tc) for sub basins 232

4.3.9 Lag time in sub basins 232

4.3.10 Muskingum parameters and channel hydraulic properties 233

4.3.11 HEC-HMS model simulation 234

4.3.12 Analysis of the model sensitivity to the changes in 267

parameters of the study area

4.3.13 Model calibration 268

4.3.14 Validation of HEC-HMS model 274

4.3.15 Runoff coefficient 277

4.3.16 Model implementation in two periods after 279

calibration model

4.3.17 The design rainfall 284

4.3.18 Model implementation in two periods (1970 and 2006) 285

for design rainfall

4.3.19 Changes in concentration time, lag time and time of 287

peak hydrograph (1970 and 2006)

4.4 Discussion 289

4.4.1 Changes in Curve Number (CN) 290

4.4.2 Time changes of the rain storms 292

4.4.3 Model calibration 295

4.4.4 The effect of land use change on peak discharge 295

and runoff volume

4.4.5 Land use change in flood 297

4.5 Conclusion 299

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5 SIMULATION OF DIFFERENT FUTURE SCENARIOS OF 303

THE BASIN IN RELATION TO THE FLOOD CONDITION


5.2 Methodology 303

5.2.1 Definition 306

5.2.2 Applying different future scenarios in the drainage basin 310

5.2.3 Estimation of concentration time, lag time and 313

time of peak hydrograph

5. 2.4 Estimation of peak discharge with different return periods 314

in each scenario

5.3 Results 314

5.3.1 Changes in curve number (CN) in each scenario 313

5.3.2 Validation of CN values for prediction scenarios 316

5.3.3 Changes in concentration time, lag time and time of peak 324

in each scenario

5.3.4 Changes in flood peak discharge with different 327

return periods in each scenarios

5.4 Discussion 330

5.5 Conclusion 330

6 IMPACT ASSESSMENT OF CHANGES IN LAND 334

CONSERVATION PRACTICES ON SOIL EROSION

AND SEDIMENT YIELD


6.2 Methodology 335

6.2.1 EPM model specifications 338

6.2.2 Determination of weight erosion intensity coefficient 340

(z) for the basin based on EPM method

6.2.3 Determination of basin specific erosion 347

6.2.4 Determination of basin sediment yield coefficient 348

6.2.5 Determination of specific sediment discharge (GSP) 349

6.2.6 Determination of total sediment discharge 350

6.2.7 Estimation of basin annual total sediment load using 351

observed suspended sediment and bed load statistics in

hydrometric station

6.2.8 Comparison of the observed sediment and the 354

estimated sediment

6.2.9 Estimation of the sediment yield in the sub basins 354

6.2.10 Estimation of specific sediment yield in the sub basins

6.2.11 Estimation of sub basins runoff depth in each sub basin 355

6.2.12 Determination of effective factors on the sub basins 356

sediment yield based on step wise multiple regressions

6.3 Results 356

6.3.1 Geomorphologic facies map 356

6.3.2 Erosion types map 358

6.3.3 Erosion intensity coefficient in each erosion types 360

6.3.4 Erosion intensity for the periods 363

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6.3.5 The total sediment discharge estimated for the 363

year 1970 and 2006

6.3.6 Correlation between water discharge and sediment discharge 364

6.3.7 Suspended loads observed in the hydrometric 368

stations during study periods

6.3.8 Comparison of the observed sediment and the 368

estimated sediment

6.3.9 Sediment yield in the sub basins 370

6.3.10 Specific sediment yield in the sub basins 371

6.3.11 Depth of runoff in each sub basin 372

6.3.12 Effective factors on the sub basins sediment yield 373

based on step wise multiple regressions

6.4 Discussion 381

6.4.1 The factors affecting sediment yield in the years 381

1970 and 2006

6.4.2 The reasons for increasing sediment yield in the period 381

1971-2006

6.4.3 The negative effects of sediment yield increase in the basin 383

6.5 Conclusion 385

7 GENERAL CONCLUSION 387

7.1 Research major contributions 389

7.2 Research benefits 390

7.3 Suggestions and recommendations for future research 392

REFERENCES/BIBILIOGRAPHY 393

APPENDICES 408

BIODATA OF STUDENT 437

LIST OF PUBLICATIONS 438

Documents

EFFECTS OF CONVERSION OF RANGELAND TO DRY FARMING … fileuniversiti putra malaysia effects of conversion of rangeland to dry farming on surface runoff, soil erosion and sediment yield