Resumo

Groundwater, especially aquifers, is vital for meeting water demands and addressing water stress. It constitutes about one-third of the global water supply. Unsustainable extraction, at 1-2% annually, exceeds natural replenishment rates, depleting accessible groundwater resources. Roughly 20% of the world's aquifers are overexploited (Connor & Koncagül, 2014).Transboundary aquifer agreements are essential for cooperation, conflict prevention, responsible utilization, water quality, and ecosystem preservation. Integrating the WEFE Nexus into aquifer studies is a great opportunity to advance.

Recognizing the holistic perspective that encompasses the interconnections between water, energy, food, and ecosystems, it becomes imperative to enrich the discussion on aquifer studies by integrating the concepts of the WEFE Nexus. Considering that the management of transboundary aquifers relies on agreements forged between countries, it is pertinent to investigate this topic by including it into the framework of the WEFE Nexus. Thus, the objective of this study is to understand how the water-energy-food-ecosystem Nexus context is considered in transboundary aquifer agreements.

The concept of the Water-Energy-Food-Ecosystem Nexus emerged in response to the pressing need to address the complex interconnections among these essential resources for global sustainability (Zhang et al., 2018). The WEFE Nexus has gained widespread recognition as an essential tool for achieving sustainable development goals (SDG) and has been incorporated into the policies and strategies of many governments, international organizations, and other stakeholders worldwide (Giupponi & Gain, 2017). The Nexus approach recognizes that actions taken in one sector can significantly impact the others.

To achieve the objective, an exploratory and systematic analysis of the agreements was conducted, utilizing analytical perspectives derived from the concept of the WEFE Nexus. The study also sought to explore key issues, gaps, and opportunities related to transboundary aquifer agreements, while considering their alignment with the principles of the WEFE Nexus.

The perspectives developed were Integrated Approach, Synergies and Trade-offs, Monitoring, Stakeholders, and Governance. In this evaluation, it was observed that none of the agreements met all the created perspective. No agreement presented data demonstrating synergy among water, energy, food, and ecosystem resources, nor did they provide guidelines regarding trade-offs between these resources. About Monitoring, Stakeholders, and Governance perspectives, there are a gap of opportunities to improve the agreements and reach the WEFE Nexus objectives.

The WEFE Nexus approach seeks to achieve a better balance in the use of natural resources critical for human well-being. However, as demonstrated in this study, technical improvements are necessary within the agreements, considering the individual characteristics and needs of each aquifer within the context of the WEFE Nexus. The main contributions of this research are expected to offer a fresh perspective to the discussion on the management and governance of transboundary aquifers. It goes beyond the issue of water alone and considers the other resources intertwined within this context.

Connor, R., & Koncagül, E. (2014). Water and Energy. Retrieved from Paris: https://unesdoc.unesco.org/ark:/48223/pf0000225741 Giupponi, C., & Gain, A. K. (2017). Integrated spatial assessment of the water, energy and food dimensions of the sustainable development goals. Regional Environmental Change, 17, 1881-1893. Zhang, C., Chen, X., Li, Y., Ding, W. & Fu, G. (2018). Water-energy-food nexus: Concepts questions and methodologies. Journal of Cleaner Production, 195, 625-639.