Social, technological, and environmental systems have become increasingly interconnected. Integrated problems arising between embedded water, energy, and food systems, require political and strategic cooperation between the actors involved at multiple governance levels. A holistic design approach is needed to guide the inherent decision-making processes. In this article, we developed a normative decision-making framework based on System of Systems Engineering (SoSE) and demonstrated how it can help to foster the cross-sectoral design of solutions to these interlinked water, energy, and food issues. The actors involved in our case study demonstrated a strong interest in collaborating across sectors and participating in the transition to cross-sectoral and sustainable resource management practices. However, experts from science and practice face a high degree of uncertainty when they design solutions to cope with the existing regional problems. As almost all regions of the world are highly integrated in national and global markets, future research might consider conducting larger research projects that also link the design approaches to inter-regional, national, and international levels. Our methodological approach illustrates how such a project could be structured on a regional level and identifies the processes that are important to consider.

An increasing number of sustainable development strategies (SDS) is being developed for cities, municipalities and countries. The design of such strategies is inherently complex. This is a result from intricate relationships between different SDS on different levels, and a large number of requirements that need to be addressed in strategy implementation. A particular challenge is the integration of strategies across different governance levels (e.g., city, federal, and national levels). Methodologies are currently lacking to systematically design SDS which take the full complexity of the dependencies of the strategies into account. In this article, we propose a participatory requirements analyses approach to support strategy building across governance levels. Experience from systems engineering (SE) has shown, that requirements are the basis for designing systems or strategies. We elicit requirements by applying a participatory modeling approach with causal-loop diagrams in an individual interview setting. To illustrate our approach, we test the developed design approach and focus on the interdependencies between SDS at the city level (i.e., the cities of Berlin and Hamburg) and the German national SDS. The design process reveals critical factors which are needed for the overall success of the strategies. The resulting causal models reveal that despite coordination activities of the regional objectives with the national targets, trade-offs exist between the strategies regarding the underlying conditions for their implementation (e.g., national law, federal and state law). In addition, the level of detail of requirements for certain objectives at the national level and across sectors is too general. This hinders the emergence of system-wide co-benefits of possible solution strategies. Requirements analysis can highlight interdependencies, such as trade-offs and synergies, between strategies at multiple governance levels and, based upon this, can support a more coherent strategy design.