Katrin Pakizer

As climate change creates significant challenges for both the environment and society, potential mitigation and adaptation solutions are widely discussed. Yet, neither challenges nor their potential solutions automatically reach the political agenda or lead to a policy decision. The Multiple Streams Framework (MSF) examines dynamics at the level of problems, solutions, and political context to understand why a given issue reaches the political agenda. This article applies the MSF to the issue of water reuse—a promising solution to addressing increasing water scarcity and droughts—which has not been taken up by the political agenda systematically. The analysis compares Swiss substates and examines how configurations of four key conditions—drought experiences, agenda influence from neighboring countries, technical capacities, and political strategies—affect the emergence of water reuse on the political agenda. Results of the Qualitative Comparative Analysis (QCA) suggest that configurations of these conditions indeed matter more than any single condition. While political context shows little influence, problem and (potential) solution dynamics are crucial for understanding the prominence of water reuse on the political agenda. The article emphasizes the importance of a holistic and non‐linear understanding of agenda‐setting dynamics as a configuration of several conditions, especially given that agenda‐setting precedes policy action on pressing climate change‐related challenges.

Over 80% of the world's wastewater is discharged untreated, making reuse a widely underutilised strategy for addressing water scarcity. Due to the complexity of implementing water reuse systems, supportive governance conditions are required to steer this process and overcome barriers. Insights from water governance and sustainability transitions literature suggest that configurations of governance‐related conditions, such as the extent of regulatory certainty, economic incentives, social acceptance, innovation capacity and contextual conditions of water scarcity, influence water reuse. Previous research has explored the barriers to water reuse, focusing on isolated case studies leaving the question of how these conditions interact to enable implementation largely unresolved. This study applies Fuzzy Set Qualitative Comparative Analysis across 15 international cases to identify configurations of conditions that enable water reuse, moving beyond individual drivers to map archetypal pathways. We found three distinct pathways to successful implementation. First, low regulatory uncertainty alone was sufficient to enable reuse, underscoring the foundational role of regulatory frameworks. Second, high social acceptance—rooted in public trust, engagement, and participatory design—can compensate for the absence of financial incentives, particularly in European contexts. However, this may be less applicable in resource‐constrained settings. The third and most globally distributed pathway confirms that water scarcity can drive reuse, but only when accompanied by social and technical readiness. The third and most globally distributed pathway confirms that water scarcity can drive reuse, but only when accompanied by social and technical readiness involving technical knowledge, skills training, interdisciplinary collaboration and opportunities for experimentation. Notably, neither water scarcity nor financial incentives emerged as necessary conditions for successful implementation across all pathways. These findings challenge commonly held assumptions about what drives water reuse and offer a more nuanced understanding of the governance configurations that can support water reuse.

The subsurface represents a critical frontier for achieving sustainability goals, yet current development approaches remain largely uncoordinated and reactive. As societal challenges intensify —from climate change mitigation to urban densification— the underground is increasingly recognized as essential infrastructure space. However, the prevailing "first-come, first-served" or "last-resort" principles governing subsurface allocation result in fragmented management practices that overlook valuable synergistic opportunities between different underground uses. The question therefore arises how subsurface synergies can be strategically integrated into regulation and planning frameworks to promote sustainable, long-term underground development.We identify three core principles that enable effective subsurface synergies: multifunctionality, circularity, and repurposing. Multifunctionality recognizes that underground spaces can serve multiple purposes simultaneously or sequentially, such as combining geothermal energy extraction with thermal energy storage, or integrating transport infrastructure with utility corridors. Circularity emphasizes cascading energy uses and resource efficiency, exemplified by utilizing waste heat from data centers for district heating networks or repurposing abandoned mines for energy storage. Repurposing extends the lifecycle of underground investments by adapting existing infrastructure to new functions, thereby reducing environmental impacts and optimizing resource utilization.Through real-world case studies, we demonstrate how these principles can be operationalized within master planning and regulatory frameworks. These cases reveal both the opportunities for synergistic subsurface planning and the governance challenges that emerge from competing uses, jurisdictional fragmentation, and temporal mismatches between planning horizons and underground resource dynamics. Moreover, our analysis highlights critical barriers to achieving subsurface synergies: inadequate legal frameworks that fail to recognize three-dimensional property rights and long-term resource claims; sectoral silos separating energy, water, infrastructure, and environmental governance; insufficient data sharing and transparency about existing and planned underground uses; and lack of coordination mechanisms between stakeholders with different temporal perspectives and priorities. Overcoming these barriers requires moving beyond conflict resolution toward proactive synergy identification and facilitation.We propose that effective subsurface governance must adopt a holistic, interdisciplinary, and integrated approach combining technical assessment with policy innovation. This includes developing spatial planning tools that visualize underground uses across multiple dimensions; establishing coordination platforms that bring together geoscientists, engineers, policymakers, and affected communities; creating legal mechanisms that recognize and incentivize synergistic developments; and implementing monitoring frameworks that track interactions between subsurface uses over time.Our presentation contributes to the session's objectives by demonstrating how governance frameworks can either enable or constrain subsurface synergies, and by providing practical insights for researchers, policymakers, and practitioners seeking to leverage underground resources more sustainably. As pressure on subsurface space intensifies, the ability to identify, evaluate, and implement synergistic solutions becomes essential for ensuring that underground development serves both current and future societal needs while respecting environmental limits and intergenerational equity.

This article presents an exploratory review of alternative governance arrangements for modular systems in the urban water sector in terms of policy instruments, organizational structure, and underlying mechanisms. We develop an analytical framework to review the literature on alternative arrangements for innovative technologies. The preliminary results highlight the importance of governmental involvement and formal policy instruments to ensure public and environmental health in the context of modular water infrastructures. This is in line with the status quo of conventional water governance arrangements. However, the findings also suggest that informal instruments supplement the formal ones and that instead of political-administrative accountability more horizontal mechanisms, such as answerability toward citizens and consumers, play an important role in the context of new water technologies.