NE Peloponnese, Greece
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Assessing Geomorphic Processes and their Potential Relationship with Archaeological Artifact Exposure – NE Peloponnese, Greece by Pamela Elizabeth Tetford A thesis submitted in conformity with the requirements for the degree of Master of Science Department of Geography University of Toronto © Copyright by Pamela Elizabeth Tetford 2017 Assessing Geomorphic Processes and their Potential Relationship with Archaeological Artifact Exposure – NE Peloponnese, Greece Pamela Elizabeth Tetford Master of Science Department of Geography University of Toronto 2017 Abstract Landscape change can be important when encountering historical artifacts. Interactions between topography, climate and human activity shape a landscape, making sediment deposits from surface erosion and fluvial transport, and the artifacts they contain, important archives. There is a potential relationship between the rate of geomorphic processes and surface artifact density. This study compares spatially variable estimates of soil loss and stream energy, as indicators of high geomorphic activity, to surface artifact finds of the Western Argolid Regional Project (WARP). Processes within the Inachos River watershed in the northeast Peloponnese, Greece, are quantified using the Unit Stream Power Erosion Deposition method (USPED) and the specific stream power approach in a Geographic Information Systems (GIS) environment. A statistically significant association is identified between surface erosion and artifact density, with the lowest artifact densities associated with the highest rates of soil loss. Knowledgeable interpretation of artifact distribution enables more accurate reconstruction of human settlement history. ii Acknowledgements I would first like to thank my supervisor, Dr. Joseph Desloges, for his invaluable input over the past year and a half. Ongoing discussions surrounding various approaches and techniques within the field of fluvial geomorphology have challenged me and helped me develop a much stronger understanding of the discipline. His suggestions and critiques of various draft sections of this thesis have led to a much improved final version. I am also greatly appreciative for his assistance in the field, and for navigating the mountainous roads (goat trails?) of the Inachos River watershed with unparalleled confidence. His generous funding of this project has provided me with an extraordinary learning opportunity. I would also like to thank my committee members, Drs. Joseph Desloges, George Arhonditsis and Dimitri Nakassis for providing valuable comments and suggestions that improve upon the final version of this thesis. I also offer thanks to Tassos Venetikidis for his assistance with the translation of Greek documents and discussion regarding the tectonic activity of the northeast Peloponnese region. I also extend my appreciation to the WARP team, for their generous hospitality during fieldwork in Greece. I thank Drs. Sarah James, Scott Gallimore and William Caraher so much for the knowledge they shared regarding the rich history and culture of the Peloponnese region, and taking the time to explain the theory and practices regarding archaeological survey methods. And to Dr. Dimitri Nakassis, I can’t begin to thank him enough for the incredible insight he provided into Greek history and culture, and his tireless assistance in the quest to find the elusive data necessary to make the completion of this project possible! His determination to find sieves and lab space to complete soil analysis was remarkable. I thank the British School of Athens for providing those laboratory facilities. Lastly, I wish to thank my family. The collective patience and understanding that they have all shown has allowed me to devote the time necessary to complete this project. Particularly to my husband, Murray, and my daughter, Sydney, who have picked up the slack at home while “mom” was working away at the computer, and without whose support this would not have been possible…thank you so much! iii Table of Contents Acknowledgements ....................................................................................................... iii Table of Contents .......................................................................................................... iv List of Tables ................................................................................................................ vii List of Figures .............................................................................................................. viii List of Appendices ........................................................................................................ ix Chapter 1: Introduction ................................................................................................ 1 1.1. Conceptual Understanding ................................................................................... 1 1.2. Defining the Problem ............................................................................................ 2 1.3. Research Objectives ............................................................................................. 4 Chapter 2: Theoretical Background ............................................................................ 5 2.1. Variable Soil Loss as an Assessment of Hillslope Stability ................................... 5 2.1.1. Evolution of the Revised Universal Soil Loss Equation ................................ 5 2.1.2. The RUSLE in a GIS Environment ............................................................... 6 2.1.2.1. The Rainfall Erosivity Factor .................................................................. 8 2.1.2.2. The Soil Erodibility Factor.................................................................... 10 2.1.2.3. Slope Length and Slope Steepness Factors ....................................... 11 2.1.2.4. The Vegetation Cover Factor .............................................................. 12 2.1.2.5. The Land Management Practices/Conservation Factor ...................... 13 2.2. Stream Power as an Indicator of Geomorphic Processes ................................... 13 2.2.1. Downstream Discharge .............................................................................. 14 2.2.2. Bankfull Width ............................................................................................ 15 2.2.3. Channel Gradient ....................................................................................... 15 2.3. The Relationship between Geomorphic Processes and Artifact Exposure ......... 16 Chapter 3: Inachos River Watershed ........................................................................ 18 3.1. Location .............................................................................................................. 18 3.2. Climate and Hydrology ........................................................................................ 19 3.3. Physiography ...................................................................................................... 21 iv 3.4. Current Land Use................................................................................................ 22 3.5. Settlement History............................................................................................... 22 Chapter 4: Methods .................................................................................................... 25 4.1. Fieldwork ............................................................................................................ 25 4.2. Soil Analysis ....................................................................................................... 26 4.3. Delineation of the Watershed .............................................................................. 26 4.4. RUSLE Calculation ............................................................................................. 26 4.4.1. Computation of the Rainfall Erosivity Factor, R.......................................... 28 4.4.2. Computation of the Soil Erodibility Factor, K .............................................. 28 4.4.3. Computation of the Slope Length and Steepness Factor, LS .................... 28 4.4.4. Computation of the Cover Management Factor, C..................................... 28 4.4.5. Computation of the Support Practice Factor, P .......................................... 29 4.5. Specific Stream Power Calculation ..................................................................... 29 4.5.1. Determination of Slope .............................................................................. 32 4.5.2. Determination of Discharge and Width Relations....................................... 32 4.5.3. Mapping Specific Stream Power ................................................................ 32 4.6. Comparing RUSLE to Artifact Density Distribution ............................................. 33 Chapter 5: Results ...................................................................................................... 35 5.1. Estimating Potential Soil Surface Erosion and Hillslope Surface Stability ........... 35 5.1.1. The R Factor (rainfall erosivity) .................................................................. 35 5.1.2. The K Factor (soil erodibility) ..................................................................... 37 5.1.3. The LS Factor (slope length-steepness) .................................................... 39 5.1.4. The C Factor (land cover index) ................................................................