Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1997 Sediment Transport Processes in Coarse Gravel- Bed Rivers: An Example From Costa Rica. Karolien Johanna zita Debusschere Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Debusschere, Karolien Johanna zita, "Sediment Transport Processes in Coarse Gravel-Bed Rivers: An Example From Costa Rica." (1997). LSU Historical Dissertations and Theses. 6415. https://digitalcommons.lsu.edu/gradschool_disstheses/6415 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. 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SEDIMENT TRANSPORT PROCESSES IN COARSE GRAVEL-BED RIVERS: AN EXAMPLE FROM COSTA RICA A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment o f the requirements for the degree of Doctor of Philosophy in The Department of Geography and Anthropology by Karolien Johanna Zita Debusschere B.S., Rijksuniversiteit van Gent, 1983 May 1997 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMX Number: 9736010 UlVfl Microform 9736010 Copyright 1997, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGEMENTS I wish to acknowledge Dr. Richard Kesel who has been my major professor throughout my graduate program. Many thanks are due to the committee members. Dr. William Davidson, Dr. Mark Walthall, Dr. Keith Henderson, and the Dean’s representative. Dr. John Day. Their support and encouragement during the final stages of this long process are greatly appreciated. I also would like to express my appreciation to Dr. Bob Miller who served earlier on the graduate committee. Although he died several years ago, he will always remain a mentor, adviser, and fnend in my professional career. I would like to thank the organizations that helped fund the field work performed for this dissertation which included the Robert C. West Graduate Student Field Research Fund, administered by the Geography and Anthropology Department at Louisiana State University; the Grants-in-Aid of Research from Sigma Xi, The Scientific Research Society; and the Grants-in-Aid awarded by the Louisiana State University Chapter of the Society of Sigma Xi. I feel privileged to have been a recipient of their awards and am encouraged to know that graduate students in the field of geography are given the opportunity to pursue their interests. A special thanks goes to my friends and “adopted” family in the United States who had to be extremely patient and tolerant of my lack of time and attention to them. Their support and acceptance of my “priorities” allowed me to dedicate my nights, week-ends, and holidays to writing this document. Last, but not least, I wish to thank my parents for giving me the education of life. They have shown me by example that integrity, commitment, and individual thought are the foundation for accomplishing one’s goals. I would not be where I am today if it had not been for them. 11 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ACKNOWLEDGEMENTS......................................................................................... ii LIST OF TABLES....................................................................................................... v LIST OF HGURES ..................................................................................................... vi LIST OF PHOTOGRAPHS......................................................................................... x ABSTRACT................................................................................................................... xii CHAPTER I: INTRODUCTION............................................................................. 1 Objectives.......................................................................................................... 4 Research Approach .......................................................................................... 4 CHAPTER 2; LITERATURE REVIEW.................................................................. 8 Alluvial Fans..................................................................................................... 8 Dynamics and Characteristics of Rows ........................................................ 18 Micromorphology ............................................................................................ 24 CHAPTERS; METHODOLOGY............................................................................ 35 Evaluation of External Factors ...................................................................... 35 Hydrology and Suspended Sediment Load ..................................... 35 Field Investigations .......................................................................................... 38 Data Collection ................................................................................... 41 Data Analysis...................................................................................... 46 CHAPTER 4: PHYSICAL SETTING..................................................................... 49 Geological Setting ............................................................................................ 49 Geomorphology and Sedimentology ............................................................. 52 Geomorphology .................................................................................. 52 Sedimentology ..................................................................................... 55 Climate.............................................................................................................. 59 Vegetation .......................................................................................................... 61 Discharge Characteristics and Suspended Sediment Loads ....................... 62 Discharge Characteristics ................................................................... 62 Suspended Sediment Load ................................................................. 68 Potential for High-Sediment-Concentration Flows ....................... 71 CHAPTER 5: ABANDONED CHANNEL REACH............................................. 75 Morphology and Geometry ............................................................................ 79 Downstream Variability of Clasts ..................................................... 89 Gradient............................................................................................... 108 Gradient and Clast-size...................................................................... 117 Sedimentology .................................................................................................. 122 Clast-Size Variation in Subfacies ..................................................... 133 Environments of Deposition ............................................................. 137 111 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Flow Conditions ................................................................................................ 143 Hydraulic Geometry ........................................................................... 143 Types of Flow .....................................................................................