Mississippi State University Scholars Junction Theses and Dissertations Theses and Dissertations 8-9-2019 Geospatial analyses of groundwater depletion and contamination: Multiscale - global, regional and local analyses Aynaz Lotfata Follow this and additional works at: https://scholarsjunction.msstate.edu/td Recommended Citation Lotfata, Aynaz, "Geospatial analyses of groundwater depletion and contamination: Multiscale - global, regional and local analyses" (2019). Theses and Dissertations. 2418. https://scholarsjunction.msstate.edu/td/2418 This Dissertation - Open Access is brought to you for free and open access by the Theses and Dissertations at Scholars Junction. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Scholars Junction. For more information, please contact [email protected]. Template C with Schemes v4.0 (beta): Created by L. Threet 2/5/19 Geospatial analyses of groundwater depletion and contamination: Multiscale - global, regional and local analyses By TITLE PAGE Aynaz Lotfata A Dissertation Submitted to the Faculty of Mississippi State University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Earth and Atmospheric Sciences in the Department of Geosciences Mississippi State, Mississippi August 2019 Copyright by COPYRIGHT PAGE Aynaz Lotfata 2019 Geospatial analyses of groundwater depletion and contamination: Multiscale - global, regional and local analyses By APPROVAL PAGE Aynaz Lotfata Approved: ____________________________________ Shrinidhi S. Ambinakudige (Major Professor) ____________________________________ John C. Rodgers, III (Committee Member) ____________________________________ Padmanava Dash (Committee Member) ____________________________________ Prem B. Parajuli (Committee Member) ____________________________________ Renee M. Clary (Graduate Coordinator) ____________________________________ Rick Travis Dean College of Arts & Sciences Name: Aynaz Lotfata ABSTRACT Date of Degree: August 9, 2019 Institution: Mississippi State University Major Field: Earth and Atmospheric Sciences Major Professor: Shrinidhi S. Ambinakudige Title of Study: Geospatial analyses of groundwater depletion and contamination: Multiscale - global, regional and local analyses Pages in Study: 174 Candidate for Degree of Doctor of Philosophy The overarching objective of this dissertation was to study groundwater resources on global, local, and regional scales. The first objective of this dissertation was to analyze the groundwater nitrate contamination in the Edwards-Trinity and the Southern High-Plains aquifers of Texas. The second was to study groundwater quality in terms of seawater intrusion in the California Coastal Basin, Upper Floridian, and North Atlantic Coastal Plain aquifers. This dissertation also provided a comprehensive overview of the groundwater level in basins at the global scale and further analyzed agricultural activities on groundwater storage in small and large basins. To achieve first objective, Ordinary Least Square (OLS) and Geographically Weighted Regression (GWR) models were used to study the relationship between groundwater nitrate contamination and land use. This dissertation further identified dominant groundwater types using USGS well data and to estimate the extent of seawater intrusion in terms of dominant ions and ocean salinity in the United States coastal aquifers. Finally, groundwater storage anomaly was quantified using Gravity Recovery and Climate Experiment (GRACE) derived variations in total Terrestrial Water Storage (TWS) and the Global Land Data Assimilation System (GLDAS). Land cover data representing a percentage of irrigated lands using groundwater resources was used to study agricultural activities on groundwater storage. Groundwater nitrate contamination was positively associated with cotton production in Southern High-Plains and Edwards-Trinity aquifers. The nitrate concentrations tended to increase as the well-depth decreased in both aquifers. Results showed that the dominant ions in the study area were Na+ and Cl- . The study concluded that Na-Cl and mixed Ca-Mg-Cl were dominant water types in the United States’ coastal aquifers. Results also indicated that seawater intrusion is occurring in the US coastal aquifers. Groundwater depletion has increased in southern Asia, western North America, and southwestern Europe due to groundwater withdrawal for agricultural use. However, farming practice is not the main reason for groundwater scarcity in South America, Africa, and Australia. DEDICATION This dissertation is dedicated to the memory of my grandparents. Also, dedicated to my beloved father Dr. Nader Lotfata, mother Mrs Farah Amirmotallebi and my brothers Dr. Aydin Lotfata and Yasin Lotfata, other family members and friends who supported me. ii ACKNOWLEDGEMENTS I would like to sincerely thank my supervisor, Dr. Shrinidhi Ambinakudige for his guidance and support throughout this study, and especially for his confidence in me. I learned from his insight a lot and I believed I learned from the best. I would also like to thank Dr. Rodgers, Dr. Dash and Dr. Parajuli for serving as committee members on my dissertation and for their constructive criticism that significantly improved the quality of this dissertation. I would like to thank Dr. Parajuli his comments and questions were very beneficial in completion of my research work. I thank Dr. Rodgers who always assured me with his encouraging words. To Dr. Dash, I was grateful for his support during my education. I express my thanks to Dr. Domenico “Mimmo” Parisi, Dr. Steven Grice, and Dr. Michael Taquino for providing research assistantship for three years in National Strategic Planning and Research Analysis Center (NSPARC). To Dr. John Brooks, I was grateful for the interpretation of some of the results presented in this dissertation. I thank the entire faculty and staff that helped me complete this journey. Also, I am thankful to all my colleagues and friends at the Department of Geosciences, especially Devon Flicker and Katerina Sergi. I will always be indebted to National Strategic Planning and Research Analysis Center (NSPARC) and the Department of Geosciences, Mississippi State University for supporting my research through a financial assistantship without which this dissertation would have never been possible. iii TABLE OF CONTENTS DEDICATION ................................................................................................................................ ii ACKNOWLEDGEMENTS ........................................................................................................... iii LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ...................................................................................................................... vii CHAPTER I. INTRODUCTION .............................................................................................................1 1.1 Background ............................................................................................................1 1.2 Estimating Groundwater Quality and Groundwater Quantity ...............................3 1.3 Why Study Groundwater Quality in Coastal and Inland Areas of the U.S.? ........8 1.4 Why Study Groundwater Quantity Throughout the World? .................................9 1.5 Study Objectives ..................................................................................................10 1.5.1 Factors Affecting the Spatial Pattern of Nitrate Contamination in Texas Aquifers (Chapter-II) .....................................................................................11 1.5.2 Degradation of Groundwater Quality in the Coastal Aquifers of the United States (Chapter-III) ........................................................................................12 1.5.3 Investigating Global Groundwater Variations in Basins of the World (Chapter-IV) ..................................................................................................13 1.6 References ...........................................................................................................16 II. FACTORS AFFECTING THE SPATIAL PATTERN OF NITRATE CONTAMINATION IN TEXAS AQUIFERS ...............................................................17 2.1 Abstract ................................................................................................................17 2.2 Introduction .........................................................................................................18 2.3 Background ..........................................................................................................21 2.4 Study Area ...........................................................................................................23 2.5 Data and Methods ................................................................................................26 2.5.2 Multivariate Statistical Analysis ....................................................................28 2.5.3 Geographically Weighted Regression ...........................................................29 2.6 Results and Discussion ........................................................................................30 2.6.2 Multivariate Statistical Analysis ....................................................................35 2.6.2 Geographically Weighted Regression ...........................................................38