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Department of Spatial Sciences School of Earth and Planetary Sciences Assessing and Predicting the Impact of Land Use and Land Cover Change on Groundwater Using Geospatial Techniques: A Case Study of Tabuk, Saudi Arabia Eman Albalawi This thesis is presented for of the Degree of Doctor of Philosophy of Curtin University December 2020 i Declaration To the best of my knowledge and belief this thesis contains no material previously published by any other person except where due acknowledgment has been made. This thesis contains no material which has been accepted for the award of any other degree or diploma in any university. Signature: Date 14/12/2020 ii Abstract Assessing land use and land cover (LULC) change is important for planning limited natural resources and the sustainable management of ecosystems. Agricultural and urban land expansion is a result of an ongoing complex interaction between policy settings, the physical environment, and socio-economic factors. Determinants driving agricultural and urban expansion contribute to the analysis of the main causes of land use change. This can assist policymakers to understand the importance of a wide range of depleting resources (e.g., groundwater) on the associated agricultural and urban land use change, particularly in the arid regions of Saudi Arabia. Substantial oil revenue and rapid growth in urban population have exerted immense pressure on groundwater resources in Saudi Arabia. Among regional cities, Tabuk in the northwest of Saudi Arabia, is an epicentre of agriculture which relies on fossil- based groundwater for irrigation and domestic use. The purpose of this study was to test the hypothesis that in the Tabuk Region the conversion of natural land ecosystems to an agricultural ecosystem impacts the hydrological cycle by changing groundwater levels. However, the unavailability of groundwater monitoring data for the region made it difficult to evaluate the impact of LULC change on water resources. Therefore, in this work a mathematical model was developed to assess the groundwater requirements for crop cultivation and water requirements for urban use over the last 30-years (1985-2015) in Tabuk city, Saudi Arabia. The hypothesis was examined through aerial multi-temporal remote sensing imagery, urban groundwater monitoring records, historical climatic variables, and field surveys, together with geospatial techniques investigating the effects of LULC change on groundwater. An object-based image analysis (OBIA) and post- classification comparison were performed to determine the spatio-temporal change in LULC. The prediction of land use and land cover was carried out through an integration of Markov chain and cellular automata (MCCA) methods. iii Agricultural crop water requirements (CWR) were estimated using an evapotranspiration (ET) based hydrological model, from which the CWR net irrigation requirements (NIR) were computed. Abstraction data from urban tube wells were utilized to determine urban water demand. The results revealed that, over the past three decades (1985-2015), 731 km2 of barren land in Tabuk was converted to agriculture (464 km2) and urban (266 km2) with an obvious increase since 1985. Accuracy of LULC change detection indicated an overall accuracy about 93% with corresponding kappa statistics about 0.90. The LULC prediction exercise showed substantial expansion of agricultural and urban lands, driven mainly by population growth in 2025 and 2035. These land conversions could accelerate land degradation which may put more pressure on meagre natural resources. Hydrological model indicated that agricultural water consumption increased approximately 4.2 x 1010 m3 during 1985-2015. Analysis of CWR suggested that maize has the highest water demand whilst wheat has the lowest water demand among the agricultural crops examined. Further, the study showed that water abstraction by urban wells increased substantially by more than 8 times in 2015 compared to 1995. The study provided a clear indication that the unsustainable use of groundwater puts Tabuk at high risk of groundwater depletion. Further changes in land use and land cover and current irrigation practices could increase soil salinity, which may result in the loss of ecosystem services and enhance land degradation. This work calls for the prudent use of resources via policy shifts and a better accounting of water usage. iv Related publications Albalawi, E., Dewan, A., & Corner, R. (2018). Spatio-temporal analysis of land use and land cover changes in arid region of Saudi Arabia. International Journal of Geomate, 14(44), 73-81. Albalawi, E., Dewan, A., & Corner, R. (2018). Predicting spatio-temporal urban growth in Tabuk, Saudi Arabia using a Cellular Automata-Markov Model. Proceedings of 156th IASTEM International Conference, Auckland, New Zealand, 5th-6th December 2018. v Acknowledgements I thank God (Allah) for helping me to finish this thesis and giving me the grace to endure until the end. I would like to express my sincere gratitude to my supervision panel namely, Dr Ashraf Dewan, Dr Sri Adiyanti, and Dr Robert Corner for their constant guidance, encouragement, and support during my research. I also extend a thank you to the thesis committee chairperson Dr Ivana Ivánová for her valuable advice during crucial stages of my research. I would like to thank my fellow graduate students and staff members at Curtin University in Perth, Australia, who helped me directly and indirectly with their suggestions and encouragement. I would especially like to acknowledge my colleague and friend Dr Claudia De Los Rios Perez, for her valuable time and advice. A very special thanks to my husband Ali and my children (Tala, Tameem, and Bader) for their great encouragement, support, and patience especially when I was heavily pre-occupied with my research. I would also like to express my deepest gratitude to my parents and siblings for their continuous prayers and support. I would especially like to acknowledge my brothers, Bader, and Mohamed, for their help during my fieldwork in Tabuk, Saudi Arabia. I am very thankful to Dr Kerri Clarke for her enormous support and encouragement and for all of the things she taught me in both my personal and academic life. I would also like to thank Dr Tauseef Gulrez for the technical support provided, and for his patience and generous contribution of time and knowledge. I greatly appreciate the support of the General Authority for Meteorology and Environmental Protection (GAMEP) of Tabuk for providing me with key climate data that I used in my research. I would like also to thank engineers, Hassan Al-Ali and Ahamed Alsarhani, from the Tabuk Water Ministry for providing me with groundwater data. Finally, I express my gratitude to the Department of Geography, Umm Al-Qura University in Makkah, Saudi Arabia for financing my PhD. vi Table of contents Declaration ............................................................................................................... i Abstract ................................................................................................................... ii Related publications ................................................................................................ iv Acknowledgements .................................................................................................. v Table of contents..................................................................................................... vi List of figures ....................................................................................................... viii List of tables ............................................................................................................ x List of acronyms ..................................................................................................... xi 1 Introduction...................................................................................................... 1 1. 1 Background .............................................................................................. 1 1.1.1 Policy drivers of land-use change in Saudi Arabia ................................ 4 1. 2 Problem statement .................................................................................... 8 1. 3 Research aim ............................................................................................ 9 1. 4 Significance .............................................................................................. 9 1. 5 Scope ......................................................................................................11 1. 6 Thesis structure .......................................................................................12 1. 7 Chapter summary ....................................................................................13 2 Literature review .............................................................................................14 2. 1 Land use and land cover change in arid and semi-arid areas .....................14 2.1.1 Remote sensing of LULC change.........................................................17 2. 2 Impact of LULC changes on groundwater ...............................................27 2.2.1 Evapotranspiration (ET) models ..........................................................30 2.2.2 Saudi Arabian (regional-based) ET model............................................32 2. 3 Chapter summary ....................................................................................33 3 Materials