The Function of Prehistoric Agricultural Systems in Sāmoa: a GIS Analysis of Resilience to Flooding
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The Function of Prehistoric Agricultural Systems in Sāmoa: A GIS Analysis of Resilience to Flooding Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Arts in the Graduate School of The Ohio State University By Craig Harris Shapiro Graduate Program in Anthropology The Ohio State University 2020 Thesis Committee Julie S. Field, Advisor Jeffrey H. Cohen, Committee Member Kristen J. Gremillion, Committee Member 1 Copyrighted by Craig Harris Shapiro 2020 2 Abstract This thesis is focused on preliminary survey of a LiDAR dataset—digital imagery that results from airborne survey, and which reveals elevation changes in the ground surface. It reveals the Sāmoan Islands as an entirely human-modified environment, consisting of a system of ditches and terraces that extend from the coast to the remote interior. These ditches and terraces served as a mitigation system that drained saturated soils and controlled flooding in the past, which in turn supported local agricultural production and maintained the integrity of the island’s soils and ecosystem. This project examines the similarities and differences between three study areas in eastern Atua province of ‘Upolu island. It suggests that prehistoric Sāmoans not only knew how to target specific soils for agricultural production, but that they knew that they needed to place ditches in order to maximize the agricultural output of an area. ii Dedication This document is dedicated to all those who have supported me and believed in my ability to complete this project, especially my parents, who are my most enduring supporters. iii Acknowledgments I would like to thank my advisor Dr. Julie Field for her guidance and insight during this project, as well as my Ohio State University committee members Drs. Kristen Gremillion and Jeffrey Cohen. Special thanks must be extended to The Center for Sāmoan Studies at The National University of Sāmoa, as they provided access to the data that allowed me to complete this project. Lastly, a loving thank you to my parents, brother, and extended family for their support throughout this endeavor. iv Vita Education: May 2015……………………………………Bachelor of Arts Degree in Sociology and Anthropology, Washington & Lee University, Graduating GPA 3.414 May 2020……………………………………Pursuing Masters of Arts in Anthropology, The Ohio State University, Current accumulative GPA 3.870 Professional Experience and Employment: Fall 2019 – Spring 2020……………………. Graduate Teaching Assistant, The Ohio State University Fall 2018 – Spring 2020……………………. University Fellow, The Ohio State University October, 2015 – December, 2017……………United States Peace Corps Volunteer, Peace Corps – Sāmoa August – September, 2015………………………Contract Archaeologist/Drone Operator, Corporacion Nacional Forestal – Te Peu, Easter Island (Rapa Nui), Chile v July – August, 2015……………………………. Archaeological Field Technician, Washington & Lee University April, 2013 – May, 2015……………………….. Field Archaeologist/Drone Operator, Clark Honors College, University of Oregon July – August, 2013……………………………..Research Assistant, Australian National University and The Vanuatu Cultural Centre – Tafea Province Educational Experiences: April – May, 2014……………………………….ANTH 377, Field Methods in Archaeology, Washington and Lee University May – July, 2014……………………………….. Archaeological Field School at Heraclea Sintica American Research Center in Sofia, Bulgaria July – August, 2014……………………………..Dig in the Roman City of Sanisera and GIS applied in Archaeology, The Sanisera Archaeological Institute for International Field Schools in Menorca, Spain Research Presentation: Spring 2019……………………………………...Society of American Archaeology 84th Annual Meeting Fields of Study Major Field: Anthropology vi Table of Contents Abstract ............................................................................................................................... ii Dedication .......................................................................................................................... iii Acknowledgments.............................................................................................................. iv Vita ...................................................................................................................................... v List of Tables ..................................................................................................................... ix List of Figures ..................................................................................................................... x Chapter 1. Introduction ....................................................................................................... 1 Is the Past the Future in Sāmoa? ..................................................................................... 2 Content of this Thesis ..................................................................................................... 4 Chapter 2. Background ...................................................................................................... 5 Pacific Island Settlement................................................................................................. 5 Geography of the Sāmoan Archipelago .......................................................................... 9 Chapter 3. Materials and Methods ................................................................................... 11 Remotely Sensed Data: LiDAR .................................................................................... 11 Identification and Analysis of Archaeological Features in LiDAR Data ..................... 13 Hydrological Analyses .................................................................................................. 16 The Distribution of Soils in Relation to Ditching ......................................................... 29 Chapter 4. Results ............................................................................................................. 31 Tafatafa ......................................................................................................................... 32 Solosolo......................................................................................................................... 32 Aleipata ......................................................................................................................... 33 Soil Analysis ................................................................................................................. 34 Chapter 5. Discussion ....................................................................................................... 37 Intensity of Ditching in Relation to Soil Type .............................................................. 37 A Dearth of Environmental Data .................................................................................. 38 vii Possible Expansions for Further Research .................................................................... 41 Key Differences Between Sāmoa and Other Pacific Archipelagoes ............................ 44 Regional Differences in Sāmoa .................................................................................... 46 Chapter 6. Conclusion ....................................................................................................... 47 Bibliography ..................................................................................................................... 50 viii List of Tables Table 1 Solosolo ditching on various soil types ............................................................... 30 Table 2 Aleipata ditching on various soil types ................................................................ 30 Table 3 Tafatafa ditching on various soil types ................................................................ 30 Table 4 Results Table........................................................................................................ 32 ix List of Figures Figure 1 A map of ‘Upolu and corresponding project areas from Green (2002). Red polygons indicate the boundaries of each of this project’s study areas in the eastern Atua province. Solosolo on the north coast, Tafatafa on the south coast, and Aleipata on the east coast. ............................................................................................................................ 3 Figure 2 Aleipata Ditches Map. The ditches are overlaid on the LiDAR image from the Center for Sāmoan Studies at the National University of Sāmoa ..................................... 14 Figure 3 Solosolo Ditches Map......................................................................................... 15 Figure 4 Tafatafa Ditches Map ......................................................................................... 16 Figure 5 Tafatafa mosaic DEM with “no data” lines. ....................................................... 18 Figure 6 Solosolo Flow Direction. 1 represents Eastward flow, 2 = SE, 4 = S, 8 = SW, 16 = W, 32 = NW, 64 = N, 68 = Null Values, 128 = NE. ..................................................... 19 Figure 7 Solosolo Flow Direction Zoom .......................................................................... 20 Figure 8 Solosolo Flow Direction Zoom with Ditches ..................................................... 21 Figure 9 Solosolo Flow Accumulation ............................................................................. 23 Figure 10 Solosolo Flow Accumulation Zoom ................................................................