The Potential of Unconventional Water in Limiting Water Scarcity

In regions with water scarcity, utilizing Unconventional Water Resources (UWRs) is an option to meet the growing demand of water. This doctoral thesis aims to improve the understanding and insights on UWRs distribution globally, with a particular focus on benefits in different climates. Twelve UWRs were studied at the global scale for better understanding state of the art of UWRs. Among them i) fog water harvesting, ii) artificial recharge of groundwater resources, and iii) iceberg water harvesting was included for more detailed analyzing in the specific case studies. As a literature review, the global distribution of twelve types of UWRs was prepared and the results showed besides geographic, economic, and political constraints, climatic conditions are the main drivers on UWRs utilization. Also, results indicated that illustrating of opportunities and challenges in UWRs utilizations can potentially help water resources managers to better planning and policymaking. The next phase of the thesis was three case studies where different environmental variables were considered for developing Fog-water harvesting Capability Index (FCI) in the Vazroud watershed, Iran (semi-humid region) using Artificial Intelligence (AI) algorithms. The results showed all AI algorithms (Generalized Dissimilarity Model: GDM, Generalized Boosted Model: GBM, Linear Additive Model: GLM, and Generalized Additive Model: GAM) had high accuracy in FCI mapping. The highest values of importance were obtained for sky view factor and the lowest for slope curvature in FCI mapping. In the second case study, changes in groundwater levels were detected by comparing data for the periods before (1985-1996) and after (1997-2018) Managed Aquifer Recharge Structure (MARS) construction. Results showed that the rate of groundwater depletion decreased after MARS construction. Also, the permeability of the MARSs have been decreased due to sedimentation and led to reducing the efficiency of the MARSs in groundwater recharge. In the third case study, opportunities and challenges in iceberg utilization were investigated across Arctic and Antarctic areas. Economic considerations and risks associated with iceberg towing were identified as the main limitations in iceberg harvesting, while environmental impacts were identified as the main challenge to exploiting this resource. Statistical analysis of ice sheets as the main sources of icebergs showed a significant decreasing trend for all months and seasons during 2005–2019. This study demonstrated that assessing the potential of unconventional water for closing the water gap is currently difficult to be quantified globally, as data only exists in the form of singular case studies. Therefore, for the direction of future studies, providing methods to prepare quantitative information about a different type of UWRs utilization can help mitigate water deficiencies.