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ÇUKUROVA UNIVERSITY INSTITUTE OF NATURAL AND APPLIED SCIENCES Ph.D. THESIS Akhtar ALI EVALUATING THE EFFECT OF MICRO-CATCHMENT WATER HARVESTING ON WATER AND SOIL LOSSES IN THE DRYLAND CATCHMENT DEPARTMENT

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ÇUKUROVA UNIVERSITY INSTITUTE OF NATURAL AND APPLIED SCIENCES Ph.D. THESIS Akhtar ALI EVALUATING THE EFFECT OF MICRO-CATCHMENT WATER HARVESTING ON WATER AND SOIL LOSSES IN THE DRYLAND CATCHMENT DEPARTMENT OF AGRICULTURAL STRUCTURES AND IRRIGATION ADANA, 2007 ABSTRACT Ph.D. THESIS EVALUATING THE EFFECT OF MICRO-CATCHMENT WATER HARVESTING ON WATER AND SOIL LOSSES IN THE DRYLAND CATCHMENT Akhtar ALI ÇUKUROVA UNIVERSITY INSTITUTE OF NATURAL AND APPLIED SCIENCES DEPARTMENT OF AGRICULTURAL STRUCTURES AND IRRIGATION Supervisor : Prof. Dr. Attila YAZAR Year : 2007, Pages: 255 Jury : Prof. Dr. Selim KAPUR Prof. Dr. Cafer GENÇOĞLAN Asst. Prof. Dr. Fatih TOPALOĞLU Asst. Prof. Dr. Erhan AKÇA Micro-catchment water harvesting (MCWH), by inducing and conserving surface runoff, can alleviate the water stresses in arid environments. It brings the changes in land surface, concentrates local runoff at plant location and reduces the downstream flows. It has serious implications on the water and soil losses as well as survival and growth of vegetative cover. This study evaluated the effects of the MCWH on the water, soil and vegetation in an area with an annual rainfall about 110 mm. A small catchment of 2.5 km 2 was equipped with weather station, runoff stage sensors, runoff plots, bridge frames and Gerlach troughs to measure runoff and sediment loss at micro-catchment, site/rill and catchment scales. RUSLE2 model was used to compute the sediment delivery across the ridges. The results revealed that the rainfall is too low to support rainfed agriculture, but with 4 mm threshold value for runoff generation, the MCWH can capture a runoff between 5 and 80% of incidental rainfall that can help in rehabilitation of the range. At microcatchment scale, the annual runoff yield was between 200 and 400 m 3 ha -1, which reduced to about half at the site scale and increased to 425 m 3 ha -1 at the catchment scale. High contribution of the upper catchment raised the runoff yield at catchment scale. The annual sediment yield was about 1.6 times higher with MCWH (1.2 Mg ha -1 yr -1 ) than the control (0.77 Mg ha -1 yr -1 ). However, the sediment delivery across the ridges was less than 1/5 th of the sediment loss. At the catchment scale, the annual sediment yield was about 1.5 Mg ha -1, which was due to the contribution of gully erosion. On an average, the sediment yield in the study area was below the soil loss tolerance limits set by the different studies elsewhere. The study estimated the effective life of the MCWH structures between 20 and 30 years. It concluded that the MCWH increased the shrub survival rate from less than 5% for control to about 70% with MCWH. It has been found that Atriplex halimus recorded high survival and growth rates and found best suited for this area. The study showed that the MCWH induced local runoff, but it did not affect the runoff yield at the catchment scale adversely. Keywords: Micro-catchment water harvesting, runoff, soil loss, soil-water, shrub survival and growth. i ÖZ DOKTORA TEZİ KURAK ALANLARDA MİKRO-HAVZA SU HASADININ SU VE TOPRAK KAYIPLARINA ETKİSİNİN DEĞERLENDİRİLMESİ Akhtar ALI ÇUKUROVA ÜNİVERSİTESİ FEN BİLİMLERİ ENSTİTÜSÜ TARIMSAL YAPILAR ve SULAMA ANABİLİM DALI Supervisor : Prof. Dr. Attila YAZAR Year : 2007, Pages: 255 Jury : Prof. Dr. Selim KAPUR Prof. Dr. Cafer GENÇOĞLAN Yrd. Doc. Dr. Fatih TOPALOĞLU Yrd. Doc. Dr. Erhan AKÇA Mikro-havza su hasadı (MCWH) teknikleri, yüzey akış sularını biriktirerek, kurak alanlarda su stresinin etkilerini azaltabilir. Bu teknik arazi üzerinde bir değişikliği gerektirir ve yersel yüzey akış sularını bitki yetiştirilen noktalarda biriktirerek aşağı doğru olan yüzey akış miktarını azaltır. Ayrıca, bu teknik toprak ve su kayıpları üzerinde önemli etkilere sahip olup aynı zamanda vejetasyonun canlı kalmasına yardımcı olur. Bu çalışmada yıllık ortalama yağışı 110 mm olan bir alanda mikro-havza su hasadı (MCWH) tekniklerinin su, toprak ve vejetasyon üzerine etkileri değerlendirilmiştir. Alanı 2.5 km 2 olan küçük bir havzada yürütülen bu araştırmada otomatik iklim istasyonu, yüzey akış sensörleri, yüzey akış parselleri, mikro-havzada, oyuntuda ve havza düzeyinde yüzey akışı, sediment kayıplarını ölçmek için Gerlach aparatı gibi aygıtlar kullanılmıştır. Ayrıca, RUSLE2 Modeli sırtlar arasında sediment taşınımını hesaplamak amacıyla kullanılmıştır. Araştırma sonuçları çalışmanın yapıldığı alanda düşen yağışların kuru tarımı sürdürebilmek için yeterli olmadığını göstermiştir. Ancak, yüzey akışın oluşabilmesi için en az 4 mm lik bir yağışa gereksinim olduğu belirlenmiştir. Mikro-havza su hasadı tekniği ile yüzey akışın %5-80 nin mera alanlarının iyileştirilmesinde yararlı olabileceği kestirilmiştir. Mikro-havza ölçeğinde yıllık yüzey akış miktarı m 3 ha -1 arasında belirlenmiştir. Araştırmanın yapıldığı küçük havza bazında bu değer yarı yarıya azalmış, ancak tüm havza bazında ise 425 m 3 ha -1 olmuştur. Yıllık sediment miktarı mikro-havza su hasadı tekniğiyle kontrol konusuna göre 1.6 kat daha fazla bulunmuştur. Ancak, sırtlara ulaşan sediment miktarı toplam sediment kayıplarının 1/5 inden daha az olmuştur. Havza bazında yıllık sediment verimi oyuntu erozyonunu katkılarıyla 1.5 Mg ha -1 belirlenmiştir. Çalışma alanında. Belirlenen ortalama sediment verimi başka alanlarda yapılan çalışmalardaki izin verilebilir toprak kayıplarından daha düşük bulunmuştur. Çalışmada mikro-havza su hasadı yapılarının ömürlerinin yıl arasında olabileceği tahmin edilmiştir. Ayrıca, mikro-havza su hasadı tekniğinin canlı çalı oranını kontrol parsellerindeki %5 e karşılık %70 e çıkardığı gözlenmiştir. Atriplex helimus çalısının çalışmada denemeye alınan diğer çalılara kıyasla daha fazla canlı kalma özelliğine sahip olduğu da ayrıca belirlenmiştir. Çalışma sonuçları, mikro-havza su hasadı uygulamasının yüzey akışı artırdığı ancak havza bazında yüzey akışa etkisinin fazla olmadığını göstermiştir. Anahtar kelimeler: Mikro-havza su hasadı, toprak kaybı, toprak suyu, çalı canlı kalma oranı ii ACKNOWLEGEMENT I gratefully acknowledge and sincerely thank my advisor Prof. Dr. Attila Yazar, Professor, Department of Agricultural Structures and Irrigation of Çukurova, University for his efficient guidance, encouragement and support from the start to the completion of this dissertation. He has always been keen to see that the results of the research are relevant and replicable. My special thanks go to Prof. Selim Kapur, Dr. Fatih Topaloğlu, Prof. Riza Kanber and other teachers and students from the department for their constructive views and encouragement during the seminars. I am especially grateful to Dr. Mahmoud Solh, Director General, Dr. William Erskine, Assistant Director General and Dr. Theib Oweis, Director, Integrated Water and Land Management Program and other colleagues from ICARDA for their generous support. The valuable suggestions by Drs. Zuhair Masri and Adriana Bruggeman; review by Dr. Fadel Rida; and editing by Mr. Venkataramani Govidan are gratefully acknowledged. The cooperation rendered by the project staff from Syria, namely Mr. Atef Abdal Aal, National Project Coordinator; General Commission for Scientific Agricultural Research (GCSAR), Mr. Kasem Salameh, Director, Mehesseh Research Center, Ms. Amira Khazal, Project Engineer, and Messer Ahmad Abdalla and Aymin Bakhit in project implementation and data collection is highly appreciated. The author wishes to acknowledge the help of the ICARDA staff namely Messer Pierre Hayek, Ali Haj-Dibo, Jihad Abdalla and Issam Halimeh in the data collection. Particular thanks are due to Ms. Rima El-Khatib for formatting the publication. Administrative support by the ICARDA and the University staff is deeply acknowledged. I acknowledge the SWISS Development Cooperation (SDC) for its generous funding the Vallerani Water Harvesting Project, which made this study possible. Most importantly, the completion of this study is not my achievement alone. Credits are due to my father, late mother, my wife, daughter and son, who have endured great difficulties with me, and always encouraged me to pursue the study. iii CONTENTS PAGE ABSTRACT...I ÖZ...II ACKNOWLEGEMENT...III CONTENTS...IV LIST OF FIGURES...IX LIST OF PHOTOS...XIII LIST OF TABLES...XIV ABBREVIATIONS AND SYMBOLS...XVII 1. INTRODUCTION The Drier Environment Water Harvesting: An Unrealized Potential of Dryland Catchments Evaluation Rationale Preposition Objectives Scope of Work LITERATURE REVIEW Context Dryland Catchments and Hydro-Sediment Process Runoff Generation Mechanisms and Assessment Methods Rainfall Catchment Area Main Abstraction and Rainfall Excess Transformation of Rainfall Excess into Direct Runoff Unit Hydrograph Approach Overland Flow and Kinematic Wave Model Soil Erosion by Water Erosion Perspective Water-erosion Mechanism and Process Splash Effect and Particle Detachment Interrill Erosion Rill Erosion...24 iv 2.4.6 Surface Crusting and Sealing Other Main Factors Affecting Interrill and Rill Erosion Universal Soil Loss Equation for Sheet and Rill Erosion Revised Universal Soil Loss Equation (RUSLE) Modified Universal Soil Loss Equation (MUSLE) Gully Erosion What is Gully? Gully Development Assessment of Gully Erosion Water Harvesting Need of Water Harvesting for Dryland Agriculture Development in Water Harvesting Water Harvesting Definitions and Systems Emerging Trends in Water Harvesting Micro-catchment Water Harvesting (MCWH) Hydraulics of MCWH MATERIALS AND METHODS The Research Environment Research Approach Setting up Research Diagnostic Analysis Research Site Development Instrumentation Soil Characterization Soil Sampling and Analysis Some Physical and Chemical Properties of Soil Aggregate Stability Analysis Macro-aggregate Analysis: Wet Sieving Micro-aggregate Analysis: Wet Sieving Bulk Density Rainfall Measurement and Analysis Data Source Long-term Rainfall Data...62 v 3.5.3 Rainstorm Erosivity Soil Moisture Measurement and Analysis Runoff Measurement and Analysis Runoff Measurement at Micro-catchment Scale by Runoff Plot Method Runoff Assessment at the Site Scale by Soil-Water Accounting and Water Balance Catchment-Scale Runoff Estimation by Measuring Stage Hydrograph Measurement of Erosion by Rainfall-runoff Erosion Measurement at Plot Scale Runoff Plot Method Gerlach Trough Method Erosion Measurement in Rill and Inter-Rill Scale General Measurement of Sheet Erosion by Pin-grid Method in Inter-Rill Area Measurement of Erosion/Deposition in Rills Cross-sections Measurement of Sediment Yield from a Rill Catchment Erosion Measurement at Catchment Scale Measurement of Decay of Runoff Ridges Mathematical Modeling of Soil Loss Assessment with RUSLE Model Concepts Model Structure Model Suitability Shrub Survival and Growth RESULTS AND DISCUSSION Rainfall Annual Rainfall Monthly Rainfall Major Rainfall Events during the Study Period Soil Soil Properties Bulk Density...96 vi 4.2.3 Soil Properties in Relation to Water Erosion Aggregate Stability and Soil Erosion Soil-Water Temporal Variability Spatial Variability Effect of MCWH Techniques on Soil-Water Distribution of Water in Soil Layers Runoff Assessment Runoff Assessment at Micro-catchment Scale Runoff Event on 4 th May, Runoff Event on 4 th April, Runoff Event on 3 rd October, Runoff Event on 25 th October, Runoff Event on 1 st March, Runoff Event on 13 th May, Runoff Event on 18 th May, Summary of Runoff Measurements and Analysis at Microcatchment Scale Runoff Assessment at Site Scale Runoff Assessment at Catchment Scale by Measuring Stage Hydrograph Runoff Event on 4 th April, Runoff Event on 3 rd October, Runoff Event on 25 th October, Runoff Event on 11 th and 12 th of May, Runoff Event on 17 th and 18 th May, Summary of Runoff Measurement at three Different Scales Soil Erosion by Water Sediment Yield at Micro-catchment Scale Runoff Plot Method Gerlach Trough Method Discussion on Sediment Yield at Micro-Catchment Scale Water Erosion at Rill Scale vii Erosion/Deposition in Inter-Rill Area Erosion/Deposition within the Rills Sediment Yield at the Outlet of Rills Sediment Yield at Catchment Scale Sediment Enrichment Decay of MCWH Structures Estimation of Sediment Yield by RUSLE2 Model Model Conceptualization Development of Input Data Files Soil Loss and Sediment Yield Estimates Summary of Sediment Yield Tolerable Soil Loss Runoff and Soil Loss Prediction Equations Shrub Survival and Growth CONCLUSIONS AND RECOMMENDATIONS Conclusions Recommendations REFERENCES CURRICULUM VITAE ANNEX A: THEORETICAL BASIS OF RUNOFF ESTIMATE ANNEX B: EXPERIMENTAL DESIGN AND LAYOUT ANNEX C: RUNOFF AND SEDIMENT YIELD ANNEX D: SOME SELECTED PHOTOGRAPHS FROM THE STUDY AREA 232 viii LIST OF FIGURES PAGE Figure 2.1. A Flowchart Showing Hydro-sediment Processes...9 Figure 2.2. Definition Sketch of Overland Flow...18 Figure 2.3. Main Water Harvesting Systems...42 Figure 2.4. Runoff Pattern as Modified by the MCWH in the Study Site...47 Figure 3.1. Location Map of the Research Site and the Catchment...49 Figure 3.2. A Framework for MCWH Evaluation for Water and Soil Losses...51 Figure 3.3. Topography and Drainage System in the Study Site...52 Figure 3.4. Variation of Soil Depth and Slope in the Study Area...53 Figure 3.5. Problem Analysis by Using Cause and Effect Approach...54 Figure 3.6. A Typical Layout of the Micro-catchment...55 Figure 3.7. An Automatic Weather Station at Research Site (Davis Instrument Corporation, 1996)...57 Figure 3.8. Field Layout of Water and Soil Loss Monitoring Network...57 Figure 3.9. Calibration Curve for One of the Neutron Probe at Study Site (February, 2005)...66 Figure Soil-water Isohyets (45 cm Soil Horizon) in the Study Site on September Figure Typical Layout of Runoff Plots in Continuous Contour Ridge Area...68 Figure Typical Layout of Runoff Plots in Intermittent Contour Ridge Area...69 Figure Rainfall, Runoff and Infiltration Processes in a Micro-catchment...70 Figure Sharp-crested Weir and Automatic Data Sensor to Record Real-time Stage Hydrograph...73 Figure Gerlach Trough for Soil Loss Measurement at Micro-catchment Scale...77 Figure A Typical Layout of Rill and Interrill Area with MCWH Structures...78 Figure Catch-trap for Measurement of Sediment Yield at Rills Scale...81 Figure Sedimentation at Immediate Upstream of a Weir...81 Figure Bridge Frame for Ridge-decay Measurement...82 Figure 4.1. Accumulative Annual Rainfall in Relation to Years of Record...86 Figure 4.2. Rainfall Anomaly Index (+ve and ve) for Partial Rainfall Series...88 Figure 4.3 (a). Cumulative Departure Index of Annual Rainfall (Partial Series)...89 Figure 4.3 (b). Cumulative Departure Index of Annual Rainfall (Complete Series).89 ix Figure 4.3 (c). Cumulative Departure Index of Annual Rainfall at Qaryatin...90 Figure 4.4. Precipitation to Evapotranspiration Ratio (P/E o ) at Qaryatin...91 Figure 4.5. Rainfall Hyetograph on 4 th May, Figure 4.6. Rainfall Hyetograph on 4 th April, Figure 4.7. Rainfall Hyetograph on 2 nd October, Figure 4.8. Rainfall Hyetograph on 23 rd and 24 th October, Figure 4.9. Rainfall Hyetograph on 1 st March, Figure Rainfall Hyetograph on 10 th and 11 th May, Figure Rainfall Hyetograph on 17 th May, Figure Temporal Variations of Soil-Water in Relation to Event Rainfall Figure Spatial Variability of Soil-water in the Study Area Figure Distribution of Soil-Water in Different Soil Layers Figure Soil-water Distribution after 36 hours of Rainfall on 24 th Oct, Figure Soil-water Distribution during Rainless Period (28 August 2006) Figure Runoff Yield and Coefficient for Different Micro-catchment Areas..109 Figure Runoff per Unit Area for MCWH Techniques and Treatments Figure Runoff Yield and Coefficient for Micro-catchment Areas Figure Runoff Yield in Relation to MCWH Techniques and Treatments Figure Runoff Yield and Runoff Coefficient in Relation to Micro-catchment Area Figure Runoff per Unit Area in Relation to MCWH Techniques and Treatments Figure Runoff Yield and Coefficient for various Micro-catchment Areas Figure Runoff per Unit Area for MCWH Techniques and Treatments Figure Runoff Yield and Runoff Coefficient in Relation to Micro-catchment Area Figure Runoff per Unit Area in Relation to MCWH Techniques and Treatments Figure Runoff Yield and Runoff Coefficient in Relation to Micro-catchment Area Figure Runoff per Unit Area in Relation to MCWH Techniques and Treatments Figure Runoff Yield and Coefficient for Micro-catchment Areas Figure Runoff per Unit Area for MCWH Techniques and Treatments x Figure Runoff Yield in Relation to Event Rainfall for Runoff Plot Method..118 Figure Runoff Yield in Relation to Rainfall Amount at Site Scale for Different MCWH Techniques and Treatments Figure Discharge Hydrograph at Weir-1 on 4 th and 5 th April Figure Computed Discharge Hydrograph at Weir-2 for Rainfall on 4 th and 5 th April Figure Computed Discharge Hydrograph at Weir-3 on 4 th and 5 th April Figure Discharge Hydrograph at Weir-2 on 3 rd October, Figure Discharge Hydrograph on 24 th 25 th October 2006 at Weir Figure Discharge Hydrograph on 24 th and 25 th October 2006 at Weir Figure Discharge Hydrograph on 24 th and 25 th October 2006 at Weir Figure Discharge Hydrograph on May, 2007 at Weir Figure Discharge Hydrograph on 11 th and 12 th May, 2007 at Weir Figure Discharge Hydrograph on 11 th and 12 th May, 2007 at Weir Figure Rainfall and Runoff Hydrograph on 17 th and 18 th May, 2007 at Weir Figure Rainfall and Runoff Hydrograph on 17 th and 18 th May, 2007 at Weir Figure Rainfall and Runoff Hydrograph on 17 th and 18 th May, 2007 at Weir Figure Annual Sediment Rate as a Function of Micro-catchment Area Figure Unit Sediment Rate as a Function of Event Rainfall Lumped over Micro-catchment Areas Figure Annual Sediment Rate in Relation to MCWH Techniques and Treatment Figure Annual Sediment Rate as a Function of Micro-Catchment Area (Gerlach Trough Method) Figure Sediment Yield in Relation to Runoff Yield at Micro-catchment Scale Figure Decay of MCWH Structures in Relation to Time Figure Annual Sediment Yield in Relation to Slope Length under Control Conditions Figure Shrub Survival in Relation to MCWH Techniques and Treatments Figure Shrub Growth in Relation to Species Figure Shrub Growth in Relation to Different MCWH Techniques and Treatments xi Figure Shrub Growth in Relation to Time Figure C-1.1. Relationship between Micro-Catchment Area and Sediment Yield for Rainfall Event on May 5, Figure C-1.2. Relationship between Micro-Catchment Area and Sediment Yield for Rainfall Event on April 4, Figure C-1.3. Relationship between Micro-Catchment Area and Sediment Yield for Rainfall Event on October 3, Figure C-1.4. Relationship between Micro-Catchment Area and Sediment Yield for Rainfall Event on October 25, Figure C-1.5. Relationship between Micro-Catchment Area and Sediment Yield for Rainfall Event on March 1, Figure C-1.6. Relationship between Micro-Catchment Area and Sediment Yield for Rainfall Event on May 12, Figure C-1.7. Relationship between Micro-Catchment Area and Sediment Yield for Rainfall Event on May 18, xii LIST OF PHOTOS PAGE Photo 1. An Automatic Weather Station at the Study Site Photo 2. Automatic Rain Gauge at the Site for Rainfall Measurement Photo 3. Use of Total Station Maintained the Accuracy in Layout of the Structures232 Photo 4. The Work on the Construction of Weir is in Progress Photo 5. Construction of Weirs in Gullies and Automatic Data Loggers Facilitated Real-time Measurement of Stage Hydrographs Photo 6. Data Logging for Each Runoff Event Photo 7. Accuracy of Data Logger Requires a Regular Battery Voltage Check Photo 8. Sediment in Front of the Weirs was Measured for each Runoff Event Photo 9.
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