UNIVERSITI PUTRA MALAYSIA

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1 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

2 EFFECTS OF CONVERSION OF RANGELAND TO DRY FARMING ON SURFACE RUNOFF, SOIL EROSION AND SEDIMENT YIELD IN KARDEH DRAINAGE BASIN, IRAN 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

3 DEDICATION To my dear wife and best friend, Shideh and our son, Pouya Without her support, I could not get through such grueling task. ii

4 Abstract of the thesis presented to the Senate of Universiti Putra Malaysia in fulfillment of the requirement for the degree of Doctor of Philosophy EFFECTS OF CONVERSION OF RANGELAND TO DRY FARMING ON SURFACE RUNOFF, SOIL EROSION AND SEDIMENT YIELD IN KARDEH DRAINAGE BASIN, IRAN 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 iii

5 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 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 (R 2 = 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. iv

6 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 Pengerusi: Fakulti: Oleh FARID SAEIDYAN Oktober 2012 Professor Madya Wan Nor Azmin B Sulaiman, PhD 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 v

7 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 Analisis regresi berbilang menunjukkan bahawa 70% daripada perubahan dalam hasil endapan dalam tahun 2006 adalah kerana kesan yang meningkat dalam pertambahan kawasan perladangan kering (R 2 = 70%, α <0.05). vi

8 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. vii

9 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 viii

10 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. ix

11 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 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 Faculty of Environmental Studies Universiti Putra Malaysia (Internal Examiner) Mohd Amin bin Mohd Soom, PhD Professor Faculty of Engineering Universiti Putra Malaysia (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 Universiti Putra Malaysia Date: 21 March 2013 x

12 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 Faculty of Environmental Studies Universiti Putra Malaysia (Chairperson) Firuz Ramli, PhD Associate Professor Faculty of Environmental Studies Universiti Putra Malaysia (Member) Majid Yasoori, PhD Professor Ferdowsi University Mashhad, I.R.Iran (Member) BUJANG BIN KIM HUAT, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia Date: xi

13 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 xii

14 TABLE OF CONTENTS Page DEDICATION ABSTRACT ABSTRAK AKNOWLEDGEMENTS APPROVAL DECLARATION LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS AND ABBREVIATIONS CHAPTER ii iii v viii x xii xviii xxv xxxi 1 INTRODUCTION Flood, erosion and sediment yield Scope of the problem Hypotheses Research objectives and approach Significance of study 11 2 LITERATURE REVIEW Land use definition Types of land use The land use situation in Iran Flood definition Conversion of precipitation to runoff The flood hydrograph and its different sections The factor effecting on the hydrograph shape The effects of land use and vegetation cover changes 25 on the drainage basin flooding Approaches for investigation the effects of changing in 31 vegetation cover on the hydrological reaction in a basin The hydrological models of precipitation-runoff simulation Runoff routing The application of geographic information system 44 (GIS) in the hydrological models Flooding characteristics in Iran Erosion definition Different types of water erosion Factors contributing to soil degradation and erosion 53 in the world 2.4. Sediment definition Sediment yield Sediment yield origins 56 xiii

15 2.4.3 The factors affecting on sediment yield in the drainage 58 basins Soil degradation and erosion in Iran Summary of chapter 65 3 THE STUDY AREA Description of the study area Physiography Drainage network Preparation of drainage basin map and delineating 72 basin and sub-basins boundary Channel density Shape of the drainage basin Preparation of Digital Elevation Model (DEM) Basin slope Climate Climatology station network Geology Pedology Investigation of land resources Hydro meteorological networks Mareshk station Al station Koshkabad station Vegetation cover Agriculture land use Demography EVALUATION OF LAND USE CHANGE FROM RANGELAND 109 TO DRY FARMING ON FLOOD EVENTS 4.1 Introduction Methodology Preparing the vegetation and land use map in Preparing the vegetation and land use map in The investigation of changes in land use between 127 years Preparing of the soil hydrological groups map CN determination of different land uses in each sub basins Investigation trend of flood occurrence in Kardeh 133 drainage basin Selection of observed flood hydrograph Collection of total daily rainfall recorded in the stations Determining spatial distribution of rainfall in sub basins Determining temporal distribution of rainfall in sub basins Calculation of concentration time (T c ) for sub basins Method on calculation of lag time in sub basins Flood routing in the river of the study area HEC- HMS model specifications 153 xiv

16 Data input to HEC-HMS model Analysis of the model sensitivity to the changes in 166 parameters of the study area Selection of model calibration for the study area Selection of model validation for the study area Using the model Calculation of runoff coefficient Model implementation in two periods after 172 calibration model Determination of the design rainfall Model implementation in two periods (1970 and 2006) 177 for design rainfall Changes in concentration time, lag time and time 177 of peak hydrograph (1970 and 2006) 4.3 Results Land use map in 2006 for the study area Land use map in 1970 for the study area Changes in land use between the years Soil hydrological groups map for the study area Curve number maps for the basin Spatial distribution of rainfall in basin area Temporal distribution of rainfall in basin rainfall Concentration time (T c ) for sub basins Lag time in sub basins Muskingum parameters and channel hydraulic properties HEC-HMS model simulation Analysis of the model sensitivity to the changes in 267 parameters of the study area Model calibration Validation of HEC-HMS model Runoff coefficient Model implementation in two periods after 279 calibration model The design rainfall Model implementation in two periods (1970 and 2006) 285 for design rainfall Changes in concentration time, lag time and time of 287 peak hydrograph (1970 and 2006) 4.4 Discussion Changes in Curve Number (CN) Time changes of the rain storms Model calibration The effect of land use change on peak discharge 295 and runoff volume Land use change in flood Conclusion 299 xv

17 5 SIMULATION OF DIFFERENT FUTURE SCENARIOS OF 303 THE BASIN IN RELATION TO THE FLOOD CONDITION 5.1 Introduction Methodology Definition Applying different future scenarios in the drainage basin Estimation of concentration time, lag time and 313 time of peak hydrograph Estimation of peak discharge with different return periods 314 in each scenario 5.3 Results Changes in curve number (CN) in each scenario Validation of CN values for prediction scenarios Changes in concentration time, lag time and time of peak 324 in each scenario Changes in flood peak discharge with different 327 return periods in each scenarios 5.4 Discussion Conclusion IMPACT ASSESSMENT OF CHANGES IN LAND 334 CONSERVATION PRACTICES ON SOIL EROSION AND SEDIMENT YIELD 6.1 Introduction Methodology EPM model specifications Determination of weight erosion intensity coefficient 340 (z) for the basin based on EPM method Determination of basin specific erosion Determination of basin sediment yield coefficient Determination of specific sediment discharge (GSP) Determination of total sediment discharge Estimation of basin annual total sediment load using 351 observed suspended sediment and bed load statistics in hydrometric station Comparison of the observed sediment and the 354 estimated sediment Estimation of the sediment yield in the sub basins Estimation of specific sediment yield in the sub basins Estimation of sub basins runoff depth in each sub basin Determination of effective factors on the sub basins 356 sediment yield based on step wise multiple regressions 6.3 Results Geomorphologic facies map Erosion types map Erosion intensity coefficient in each erosion types Erosion intensity for the periods 363 xvi

18 6.3.5 The total sediment discharge estimated for the 363 year 1970 and Correlation between water discharge and sediment discharge Suspended loads observed in the hydrometric 368 stations during study periods Comparison of the observed sediment and the 368 estimated sediment Sediment yield in the sub basins Specific sediment yield in the sub basins Depth of runoff in each sub basin Effective factors on the sub basins sediment yield 373 based on step wise multiple regressions 6.4 Discussion The factors affecting sediment yield in the years and The reasons for increasing sediment yield in the period The negative effects of sediment yield increase in the basin Conclusion GENERAL CONCLUSION Research major contributions Research benefits Suggestions and recommendations for future research 392 REFERENCES/BIBILIOGRAPHY 393 APPENDICES 408 BIODATA OF STUDENT 437 LIST OF PUBLICATIONS 438 xvii